1456 lines
36 KiB
ArmAsm
1456 lines
36 KiB
ArmAsm
/*
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* fp_util.S
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*
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* Copyright Roman Zippel, 1997. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, and the entire permission notice in its entirety,
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* including the disclaimer of warranties.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior
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* written permission.
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*
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* ALTERNATIVELY, this product may be distributed under the terms of
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* the GNU General Public License, in which case the provisions of the GPL are
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* required INSTEAD OF the above restrictions. (This clause is
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* necessary due to a potential bad interaction between the GPL and
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* the restrictions contained in a BSD-style copyright.)
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <linux/config.h>
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#include "fp_emu.h"
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/*
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* Here are lots of conversion and normalization functions mainly
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* used by fp_scan.S
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* Note that these functions are optimized for "normal" numbers,
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* these are handled first and exit as fast as possible, this is
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* especially important for fp_normalize_ext/fp_conv_ext2ext, as
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* it's called very often.
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* The register usage is optimized for fp_scan.S and which register
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* is currently at that time unused, be careful if you want change
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* something here. %d0 and %d1 is always usable, sometimes %d2 (or
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* only the lower half) most function have to return the %a0
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* unmodified, so that the caller can immediately reuse it.
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*/
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.globl fp_ill, fp_end
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| exits from fp_scan:
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| illegal instruction
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fp_ill:
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printf ,"fp_illegal\n"
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rts
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| completed instruction
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fp_end:
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tst.l (TASK_MM-8,%a2)
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jmi 1f
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tst.l (TASK_MM-4,%a2)
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jmi 1f
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tst.l (TASK_MM,%a2)
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jpl 2f
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1: printf ,"oops:%p,%p,%p\n",3,%a2@(TASK_MM-8),%a2@(TASK_MM-4),%a2@(TASK_MM)
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2: clr.l %d0
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rts
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.globl fp_conv_long2ext, fp_conv_single2ext
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.globl fp_conv_double2ext, fp_conv_ext2ext
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.globl fp_normalize_ext, fp_normalize_double
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.globl fp_normalize_single, fp_normalize_single_fast
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.globl fp_conv_ext2double, fp_conv_ext2single
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.globl fp_conv_ext2long, fp_conv_ext2short
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.globl fp_conv_ext2byte
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.globl fp_finalrounding_single, fp_finalrounding_single_fast
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.globl fp_finalrounding_double
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.globl fp_finalrounding, fp_finaltest, fp_final
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/*
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* First several conversion functions from a source operand
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* into the extended format. Note, that only fp_conv_ext2ext
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* normalizes the number and is always called after the other
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* conversion functions, which only move the information into
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* fp_ext structure.
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*/
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| fp_conv_long2ext:
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| args: %d0 = source (32-bit long)
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| %a0 = destination (ptr to struct fp_ext)
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fp_conv_long2ext:
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printf PCONV,"l2e: %p -> %p(",2,%d0,%a0
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clr.l %d1 | sign defaults to zero
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tst.l %d0
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jeq fp_l2e_zero | is source zero?
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jpl 1f | positive?
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moveq #1,%d1
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neg.l %d0
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1: swap %d1
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move.w #0x3fff+31,%d1
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move.l %d1,(%a0)+ | set sign / exp
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move.l %d0,(%a0)+ | set mantissa
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clr.l (%a0)
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subq.l #8,%a0 | restore %a0
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printx PCONV,%a0@
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printf PCONV,")\n"
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rts
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| source is zero
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fp_l2e_zero:
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clr.l (%a0)+
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clr.l (%a0)+
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clr.l (%a0)
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subq.l #8,%a0
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printx PCONV,%a0@
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printf PCONV,")\n"
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rts
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| fp_conv_single2ext
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| args: %d0 = source (single-precision fp value)
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| %a0 = dest (struct fp_ext *)
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fp_conv_single2ext:
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printf PCONV,"s2e: %p -> %p(",2,%d0,%a0
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move.l %d0,%d1
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lsl.l #8,%d0 | shift mantissa
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lsr.l #8,%d1 | exponent / sign
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lsr.l #7,%d1
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lsr.w #8,%d1
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jeq fp_s2e_small | zero / denormal?
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cmp.w #0xff,%d1 | NaN / Inf?
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jeq fp_s2e_large
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bset #31,%d0 | set explizit bit
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add.w #0x3fff-0x7f,%d1 | re-bias the exponent.
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9: move.l %d1,(%a0)+ | fp_ext.sign, fp_ext.exp
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move.l %d0,(%a0)+ | high lword of fp_ext.mant
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clr.l (%a0) | low lword = 0
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subq.l #8,%a0
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printx PCONV,%a0@
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printf PCONV,")\n"
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rts
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| zeros and denormalized
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fp_s2e_small:
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| exponent is zero, so explizit bit is already zero too
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tst.l %d0
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jeq 9b
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move.w #0x4000-0x7f,%d1
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jra 9b
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| infinities and NAN
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fp_s2e_large:
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bclr #31,%d0 | clear explizit bit
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move.w #0x7fff,%d1
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jra 9b
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fp_conv_double2ext:
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#ifdef FPU_EMU_DEBUG
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getuser.l %a1@(0),%d0,fp_err_ua2,%a1
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getuser.l %a1@(4),%d1,fp_err_ua2,%a1
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printf PCONV,"d2e: %p%p -> %p(",3,%d0,%d1,%a0
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#endif
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getuser.l (%a1)+,%d0,fp_err_ua2,%a1
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move.l %d0,%d1
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lsl.l #8,%d0 | shift high mantissa
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lsl.l #3,%d0
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lsr.l #8,%d1 | exponent / sign
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lsr.l #7,%d1
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lsr.w #5,%d1
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jeq fp_d2e_small | zero / denormal?
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cmp.w #0x7ff,%d1 | NaN / Inf?
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jeq fp_d2e_large
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bset #31,%d0 | set explizit bit
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add.w #0x3fff-0x3ff,%d1 | re-bias the exponent.
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9: move.l %d1,(%a0)+ | fp_ext.sign, fp_ext.exp
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move.l %d0,(%a0)+
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getuser.l (%a1)+,%d0,fp_err_ua2,%a1
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move.l %d0,%d1
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lsl.l #8,%d0
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lsl.l #3,%d0
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move.l %d0,(%a0)
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moveq #21,%d0
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lsr.l %d0,%d1
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or.l %d1,-(%a0)
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subq.l #4,%a0
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printx PCONV,%a0@
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printf PCONV,")\n"
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rts
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| zeros and denormalized
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fp_d2e_small:
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| exponent is zero, so explizit bit is already zero too
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tst.l %d0
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jeq 9b
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move.w #0x4000-0x3ff,%d1
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jra 9b
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| infinities and NAN
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fp_d2e_large:
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bclr #31,%d0 | clear explizit bit
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move.w #0x7fff,%d1
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jra 9b
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| fp_conv_ext2ext:
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| originally used to get longdouble from userspace, now it's
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| called before arithmetic operations to make sure the number
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| is normalized [maybe rename it?].
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| args: %a0 = dest (struct fp_ext *)
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| returns 0 in %d0 for a NaN, otherwise 1
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fp_conv_ext2ext:
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printf PCONV,"e2e: %p(",1,%a0
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printx PCONV,%a0@
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printf PCONV,"), "
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move.l (%a0)+,%d0
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cmp.w #0x7fff,%d0 | Inf / NaN?
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jeq fp_e2e_large
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move.l (%a0),%d0
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jpl fp_e2e_small | zero / denorm?
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| The high bit is set, so normalization is irrelevant.
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fp_e2e_checkround:
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subq.l #4,%a0
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#ifdef CONFIG_M68KFPU_EMU_EXTRAPREC
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move.b (%a0),%d0
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jne fp_e2e_round
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#endif
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printf PCONV,"%p(",1,%a0
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printx PCONV,%a0@
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printf PCONV,")\n"
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moveq #1,%d0
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rts
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#ifdef CONFIG_M68KFPU_EMU_EXTRAPREC
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fp_e2e_round:
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fp_set_sr FPSR_EXC_INEX2
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clr.b (%a0)
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move.w (FPD_RND,FPDATA),%d2
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jne fp_e2e_roundother | %d2 == 0, round to nearest
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tst.b %d0 | test guard bit
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jpl 9f | zero is closer
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btst #0,(11,%a0) | test lsb bit
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jne fp_e2e_doroundup | round to infinity
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lsl.b #1,%d0 | check low bits
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jeq 9f | round to zero
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fp_e2e_doroundup:
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addq.l #1,(8,%a0)
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jcc 9f
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addq.l #1,(4,%a0)
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jcc 9f
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move.w #0x8000,(4,%a0)
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addq.w #1,(2,%a0)
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9: printf PNORM,"%p(",1,%a0
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printx PNORM,%a0@
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printf PNORM,")\n"
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rts
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fp_e2e_roundother:
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subq.w #2,%d2
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jcs 9b | %d2 < 2, round to zero
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jhi 1f | %d2 > 2, round to +infinity
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tst.b (1,%a0) | to -inf
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jne fp_e2e_doroundup | negative, round to infinity
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jra 9b | positive, round to zero
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1: tst.b (1,%a0) | to +inf
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jeq fp_e2e_doroundup | positive, round to infinity
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jra 9b | negative, round to zero
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#endif
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| zeros and subnormals:
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| try to normalize these anyway.
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fp_e2e_small:
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jne fp_e2e_small1 | high lword zero?
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move.l (4,%a0),%d0
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jne fp_e2e_small2
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#ifdef CONFIG_M68KFPU_EMU_EXTRAPREC
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clr.l %d0
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move.b (-4,%a0),%d0
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jne fp_e2e_small3
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#endif
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| Genuine zero.
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clr.w -(%a0)
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subq.l #2,%a0
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printf PNORM,"%p(",1,%a0
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printx PNORM,%a0@
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printf PNORM,")\n"
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moveq #1,%d0
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rts
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| definitely subnormal, need to shift all 64 bits
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fp_e2e_small1:
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bfffo %d0{#0,#32},%d1
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move.w -(%a0),%d2
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sub.w %d1,%d2
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jcc 1f
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| Pathologically small, denormalize.
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add.w %d2,%d1
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clr.w %d2
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1: move.w %d2,(%a0)+
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move.w %d1,%d2
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jeq fp_e2e_checkround
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| fancy 64-bit double-shift begins here
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lsl.l %d2,%d0
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move.l %d0,(%a0)+
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move.l (%a0),%d0
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move.l %d0,%d1
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lsl.l %d2,%d0
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move.l %d0,(%a0)
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neg.w %d2
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and.w #0x1f,%d2
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lsr.l %d2,%d1
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or.l %d1,-(%a0)
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#ifdef CONFIG_M68KFPU_EMU_EXTRAPREC
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fp_e2e_extra1:
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clr.l %d0
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move.b (-4,%a0),%d0
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neg.w %d2
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add.w #24,%d2
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jcc 1f
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clr.b (-4,%a0)
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lsl.l %d2,%d0
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or.l %d0,(4,%a0)
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jra fp_e2e_checkround
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1: addq.w #8,%d2
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lsl.l %d2,%d0
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move.b %d0,(-4,%a0)
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lsr.l #8,%d0
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or.l %d0,(4,%a0)
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#endif
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jra fp_e2e_checkround
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| pathologically small subnormal
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fp_e2e_small2:
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bfffo %d0{#0,#32},%d1
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add.w #32,%d1
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move.w -(%a0),%d2
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sub.w %d1,%d2
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jcc 1f
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| Beyond pathologically small, denormalize.
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add.w %d2,%d1
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clr.w %d2
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1: move.w %d2,(%a0)+
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ext.l %d1
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jeq fp_e2e_checkround
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clr.l (4,%a0)
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sub.w #32,%d2
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jcs 1f
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lsl.l %d1,%d0 | lower lword needs only to be shifted
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move.l %d0,(%a0) | into the higher lword
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#ifdef CONFIG_M68KFPU_EMU_EXTRAPREC
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clr.l %d0
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move.b (-4,%a0),%d0
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clr.b (-4,%a0)
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neg.w %d1
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add.w #32,%d1
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bfins %d0,(%a0){%d1,#8}
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#endif
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jra fp_e2e_checkround
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1: neg.w %d1 | lower lword is splitted between
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bfins %d0,(%a0){%d1,#32} | higher and lower lword
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#ifndef CONFIG_M68KFPU_EMU_EXTRAPREC
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jra fp_e2e_checkround
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#else
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move.w %d1,%d2
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jra fp_e2e_extra1
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| These are extremely small numbers, that will mostly end up as zero
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| anyway, so this is only important for correct rounding.
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fp_e2e_small3:
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bfffo %d0{#24,#8},%d1
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add.w #40,%d1
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move.w -(%a0),%d2
|
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sub.w %d1,%d2
|
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jcc 1f
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|
| Pathologically small, denormalize.
|
|
add.w %d2,%d1
|
|
clr.w %d2
|
|
1: move.w %d2,(%a0)+
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ext.l %d1
|
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jeq fp_e2e_checkround
|
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cmp.w #8,%d1
|
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jcs 2f
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1: clr.b (-4,%a0)
|
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sub.w #64,%d1
|
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jcs 1f
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add.w #24,%d1
|
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lsl.l %d1,%d0
|
|
move.l %d0,(%a0)
|
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jra fp_e2e_checkround
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1: neg.w %d1
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bfins %d0,(%a0){%d1,#8}
|
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jra fp_e2e_checkround
|
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2: lsl.l %d1,%d0
|
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move.b %d0,(-4,%a0)
|
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lsr.l #8,%d0
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move.b %d0,(7,%a0)
|
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jra fp_e2e_checkround
|
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#endif
|
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1: move.l %d0,%d1 | lower lword is splitted between
|
|
lsl.l %d2,%d0 | higher and lower lword
|
|
move.l %d0,(%a0)
|
|
move.l %d1,%d0
|
|
neg.w %d2
|
|
add.w #32,%d2
|
|
lsr.l %d2,%d0
|
|
move.l %d0,-(%a0)
|
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jra fp_e2e_checkround
|
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| Infinities and NaNs
|
|
fp_e2e_large:
|
|
move.l (%a0)+,%d0
|
|
jne 3f
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1: tst.l (%a0)
|
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jne 4f
|
|
moveq #1,%d0
|
|
2: subq.l #8,%a0
|
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printf PCONV,"%p(",1,%a0
|
|
printx PCONV,%a0@
|
|
printf PCONV,")\n"
|
|
rts
|
|
| we have maybe a NaN, shift off the highest bit
|
|
3: lsl.l #1,%d0
|
|
jeq 1b
|
|
| we have a NaN, clear the return value
|
|
4: clrl %d0
|
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jra 2b
|
|
|
|
|
|
/*
|
|
* Normalization functions. Call these on the output of general
|
|
* FP operators, and before any conversion into the destination
|
|
* formats. fp_normalize_ext has always to be called first, the
|
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* following conversion functions expect an already normalized
|
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* number.
|
|
*/
|
|
|
|
| fp_normalize_ext:
|
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| normalize an extended in extended (unpacked) format, basically
|
|
| it does the same as fp_conv_ext2ext, additionally it also does
|
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| the necessary postprocessing checks.
|
|
| args: %a0 (struct fp_ext *)
|
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| NOTE: it does _not_ modify %a0/%a1 and the upper word of %d2
|
|
|
|
fp_normalize_ext:
|
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printf PNORM,"ne: %p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,"), "
|
|
move.l (%a0)+,%d0
|
|
cmp.w #0x7fff,%d0 | Inf / NaN?
|
|
jeq fp_ne_large
|
|
move.l (%a0),%d0
|
|
jpl fp_ne_small | zero / denorm?
|
|
| The high bit is set, so normalization is irrelevant.
|
|
fp_ne_checkround:
|
|
subq.l #4,%a0
|
|
#ifdef CONFIG_M68KFPU_EMU_EXTRAPREC
|
|
move.b (%a0),%d0
|
|
jne fp_ne_round
|
|
#endif
|
|
printf PNORM,"%p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,")\n"
|
|
rts
|
|
#ifdef CONFIG_M68KFPU_EMU_EXTRAPREC
|
|
fp_ne_round:
|
|
fp_set_sr FPSR_EXC_INEX2
|
|
clr.b (%a0)
|
|
move.w (FPD_RND,FPDATA),%d2
|
|
jne fp_ne_roundother | %d2 == 0, round to nearest
|
|
tst.b %d0 | test guard bit
|
|
jpl 9f | zero is closer
|
|
btst #0,(11,%a0) | test lsb bit
|
|
jne fp_ne_doroundup | round to infinity
|
|
lsl.b #1,%d0 | check low bits
|
|
jeq 9f | round to zero
|
|
fp_ne_doroundup:
|
|
addq.l #1,(8,%a0)
|
|
jcc 9f
|
|
addq.l #1,(4,%a0)
|
|
jcc 9f
|
|
addq.w #1,(2,%a0)
|
|
move.w #0x8000,(4,%a0)
|
|
9: printf PNORM,"%p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,")\n"
|
|
rts
|
|
fp_ne_roundother:
|
|
subq.w #2,%d2
|
|
jcs 9b | %d2 < 2, round to zero
|
|
jhi 1f | %d2 > 2, round to +infinity
|
|
tst.b (1,%a0) | to -inf
|
|
jne fp_ne_doroundup | negative, round to infinity
|
|
jra 9b | positive, round to zero
|
|
1: tst.b (1,%a0) | to +inf
|
|
jeq fp_ne_doroundup | positive, round to infinity
|
|
jra 9b | negative, round to zero
|
|
#endif
|
|
| Zeros and subnormal numbers
|
|
| These are probably merely subnormal, rather than "denormalized"
|
|
| numbers, so we will try to make them normal again.
|
|
fp_ne_small:
|
|
jne fp_ne_small1 | high lword zero?
|
|
move.l (4,%a0),%d0
|
|
jne fp_ne_small2
|
|
#ifdef CONFIG_M68KFPU_EMU_EXTRAPREC
|
|
clr.l %d0
|
|
move.b (-4,%a0),%d0
|
|
jne fp_ne_small3
|
|
#endif
|
|
| Genuine zero.
|
|
clr.w -(%a0)
|
|
subq.l #2,%a0
|
|
printf PNORM,"%p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,")\n"
|
|
rts
|
|
| Subnormal.
|
|
fp_ne_small1:
|
|
bfffo %d0{#0,#32},%d1
|
|
move.w -(%a0),%d2
|
|
sub.w %d1,%d2
|
|
jcc 1f
|
|
| Pathologically small, denormalize.
|
|
add.w %d2,%d1
|
|
clr.w %d2
|
|
fp_set_sr FPSR_EXC_UNFL
|
|
1: move.w %d2,(%a0)+
|
|
move.w %d1,%d2
|
|
jeq fp_ne_checkround
|
|
| This is exactly the same 64-bit double shift as seen above.
|
|
lsl.l %d2,%d0
|
|
move.l %d0,(%a0)+
|
|
move.l (%a0),%d0
|
|
move.l %d0,%d1
|
|
lsl.l %d2,%d0
|
|
move.l %d0,(%a0)
|
|
neg.w %d2
|
|
and.w #0x1f,%d2
|
|
lsr.l %d2,%d1
|
|
or.l %d1,-(%a0)
|
|
#ifdef CONFIG_M68KFPU_EMU_EXTRAPREC
|
|
fp_ne_extra1:
|
|
clr.l %d0
|
|
move.b (-4,%a0),%d0
|
|
neg.w %d2
|
|
add.w #24,%d2
|
|
jcc 1f
|
|
clr.b (-4,%a0)
|
|
lsl.l %d2,%d0
|
|
or.l %d0,(4,%a0)
|
|
jra fp_ne_checkround
|
|
1: addq.w #8,%d2
|
|
lsl.l %d2,%d0
|
|
move.b %d0,(-4,%a0)
|
|
lsr.l #8,%d0
|
|
or.l %d0,(4,%a0)
|
|
#endif
|
|
jra fp_ne_checkround
|
|
| May or may not be subnormal, if so, only 32 bits to shift.
|
|
fp_ne_small2:
|
|
bfffo %d0{#0,#32},%d1
|
|
add.w #32,%d1
|
|
move.w -(%a0),%d2
|
|
sub.w %d1,%d2
|
|
jcc 1f
|
|
| Beyond pathologically small, denormalize.
|
|
add.w %d2,%d1
|
|
clr.w %d2
|
|
fp_set_sr FPSR_EXC_UNFL
|
|
1: move.w %d2,(%a0)+
|
|
ext.l %d1
|
|
jeq fp_ne_checkround
|
|
clr.l (4,%a0)
|
|
sub.w #32,%d1
|
|
jcs 1f
|
|
lsl.l %d1,%d0 | lower lword needs only to be shifted
|
|
move.l %d0,(%a0) | into the higher lword
|
|
#ifdef CONFIG_M68KFPU_EMU_EXTRAPREC
|
|
clr.l %d0
|
|
move.b (-4,%a0),%d0
|
|
clr.b (-4,%a0)
|
|
neg.w %d1
|
|
add.w #32,%d1
|
|
bfins %d0,(%a0){%d1,#8}
|
|
#endif
|
|
jra fp_ne_checkround
|
|
1: neg.w %d1 | lower lword is splitted between
|
|
bfins %d0,(%a0){%d1,#32} | higher and lower lword
|
|
#ifndef CONFIG_M68KFPU_EMU_EXTRAPREC
|
|
jra fp_ne_checkround
|
|
#else
|
|
move.w %d1,%d2
|
|
jra fp_ne_extra1
|
|
| These are extremely small numbers, that will mostly end up as zero
|
|
| anyway, so this is only important for correct rounding.
|
|
fp_ne_small3:
|
|
bfffo %d0{#24,#8},%d1
|
|
add.w #40,%d1
|
|
move.w -(%a0),%d2
|
|
sub.w %d1,%d2
|
|
jcc 1f
|
|
| Pathologically small, denormalize.
|
|
add.w %d2,%d1
|
|
clr.w %d2
|
|
1: move.w %d2,(%a0)+
|
|
ext.l %d1
|
|
jeq fp_ne_checkround
|
|
cmp.w #8,%d1
|
|
jcs 2f
|
|
1: clr.b (-4,%a0)
|
|
sub.w #64,%d1
|
|
jcs 1f
|
|
add.w #24,%d1
|
|
lsl.l %d1,%d0
|
|
move.l %d0,(%a0)
|
|
jra fp_ne_checkround
|
|
1: neg.w %d1
|
|
bfins %d0,(%a0){%d1,#8}
|
|
jra fp_ne_checkround
|
|
2: lsl.l %d1,%d0
|
|
move.b %d0,(-4,%a0)
|
|
lsr.l #8,%d0
|
|
move.b %d0,(7,%a0)
|
|
jra fp_ne_checkround
|
|
#endif
|
|
| Infinities and NaNs, again, same as above.
|
|
fp_ne_large:
|
|
move.l (%a0)+,%d0
|
|
jne 3f
|
|
1: tst.l (%a0)
|
|
jne 4f
|
|
2: subq.l #8,%a0
|
|
printf PNORM,"%p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,")\n"
|
|
rts
|
|
| we have maybe a NaN, shift off the highest bit
|
|
3: move.l %d0,%d1
|
|
lsl.l #1,%d1
|
|
jne 4f
|
|
clr.l (-4,%a0)
|
|
jra 1b
|
|
| we have a NaN, test if it is signaling
|
|
4: bset #30,%d0
|
|
jne 2b
|
|
fp_set_sr FPSR_EXC_SNAN
|
|
move.l %d0,(-4,%a0)
|
|
jra 2b
|
|
|
|
| these next two do rounding as per the IEEE standard.
|
|
| values for the rounding modes appear to be:
|
|
| 0: Round to nearest
|
|
| 1: Round to zero
|
|
| 2: Round to -Infinity
|
|
| 3: Round to +Infinity
|
|
| both functions expect that fp_normalize was already
|
|
| called (and extended argument is already normalized
|
|
| as far as possible), these are used if there is different
|
|
| rounding precision is selected and before converting
|
|
| into single/double
|
|
|
|
| fp_normalize_double:
|
|
| normalize an extended with double (52-bit) precision
|
|
| args: %a0 (struct fp_ext *)
|
|
|
|
fp_normalize_double:
|
|
printf PNORM,"nd: %p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,"), "
|
|
move.l (%a0)+,%d2
|
|
tst.w %d2
|
|
jeq fp_nd_zero | zero / denormalized
|
|
cmp.w #0x7fff,%d2
|
|
jeq fp_nd_huge | NaN / infinitive.
|
|
sub.w #0x4000-0x3ff,%d2 | will the exponent fit?
|
|
jcs fp_nd_small | too small.
|
|
cmp.w #0x7fe,%d2
|
|
jcc fp_nd_large | too big.
|
|
addq.l #4,%a0
|
|
move.l (%a0),%d0 | low lword of mantissa
|
|
| now, round off the low 11 bits.
|
|
fp_nd_round:
|
|
moveq #21,%d1
|
|
lsl.l %d1,%d0 | keep 11 low bits.
|
|
jne fp_nd_checkround | Are they non-zero?
|
|
| nothing to do here
|
|
9: subq.l #8,%a0
|
|
printf PNORM,"%p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,")\n"
|
|
rts
|
|
| Be careful with the X bit! It contains the lsb
|
|
| from the shift above, it is needed for round to nearest.
|
|
fp_nd_checkround:
|
|
fp_set_sr FPSR_EXC_INEX2 | INEX2 bit
|
|
and.w #0xf800,(2,%a0) | clear bits 0-10
|
|
move.w (FPD_RND,FPDATA),%d2 | rounding mode
|
|
jne 2f | %d2 == 0, round to nearest
|
|
tst.l %d0 | test guard bit
|
|
jpl 9b | zero is closer
|
|
| here we test the X bit by adding it to %d2
|
|
clr.w %d2 | first set z bit, addx only clears it
|
|
addx.w %d2,%d2 | test lsb bit
|
|
| IEEE754-specified "round to even" behaviour. If the guard
|
|
| bit is set, then the number is odd, so rounding works like
|
|
| in grade-school arithmetic (i.e. 1.5 rounds to 2.0)
|
|
| Otherwise, an equal distance rounds towards zero, so as not
|
|
| to produce an odd number. This is strange, but it is what
|
|
| the standard says.
|
|
jne fp_nd_doroundup | round to infinity
|
|
lsl.l #1,%d0 | check low bits
|
|
jeq 9b | round to zero
|
|
fp_nd_doroundup:
|
|
| round (the mantissa, that is) towards infinity
|
|
add.l #0x800,(%a0)
|
|
jcc 9b | no overflow, good.
|
|
addq.l #1,-(%a0) | extend to high lword
|
|
jcc 1f | no overflow, good.
|
|
| Yow! we have managed to overflow the mantissa. Since this
|
|
| only happens when %d1 was 0xfffff800, it is now zero, so
|
|
| reset the high bit, and increment the exponent.
|
|
move.w #0x8000,(%a0)
|
|
addq.w #1,-(%a0)
|
|
cmp.w #0x43ff,(%a0)+ | exponent now overflown?
|
|
jeq fp_nd_large | yes, so make it infinity.
|
|
1: subq.l #4,%a0
|
|
printf PNORM,"%p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,")\n"
|
|
rts
|
|
2: subq.w #2,%d2
|
|
jcs 9b | %d2 < 2, round to zero
|
|
jhi 3f | %d2 > 2, round to +infinity
|
|
| Round to +Inf or -Inf. High word of %d2 contains the
|
|
| sign of the number, by the way.
|
|
swap %d2 | to -inf
|
|
tst.b %d2
|
|
jne fp_nd_doroundup | negative, round to infinity
|
|
jra 9b | positive, round to zero
|
|
3: swap %d2 | to +inf
|
|
tst.b %d2
|
|
jeq fp_nd_doroundup | positive, round to infinity
|
|
jra 9b | negative, round to zero
|
|
| Exponent underflow. Try to make a denormal, and set it to
|
|
| the smallest possible fraction if this fails.
|
|
fp_nd_small:
|
|
fp_set_sr FPSR_EXC_UNFL | set UNFL bit
|
|
move.w #0x3c01,(-2,%a0) | 2**-1022
|
|
neg.w %d2 | degree of underflow
|
|
cmp.w #32,%d2 | single or double shift?
|
|
jcc 1f
|
|
| Again, another 64-bit double shift.
|
|
move.l (%a0),%d0
|
|
move.l %d0,%d1
|
|
lsr.l %d2,%d0
|
|
move.l %d0,(%a0)+
|
|
move.l (%a0),%d0
|
|
lsr.l %d2,%d0
|
|
neg.w %d2
|
|
add.w #32,%d2
|
|
lsl.l %d2,%d1
|
|
or.l %d1,%d0
|
|
move.l (%a0),%d1
|
|
move.l %d0,(%a0)
|
|
| Check to see if we shifted off any significant bits
|
|
lsl.l %d2,%d1
|
|
jeq fp_nd_round | Nope, round.
|
|
bset #0,%d0 | Yes, so set the "sticky bit".
|
|
jra fp_nd_round | Now, round.
|
|
| Another 64-bit single shift and store
|
|
1: sub.w #32,%d2
|
|
cmp.w #32,%d2 | Do we really need to shift?
|
|
jcc 2f | No, the number is too small.
|
|
move.l (%a0),%d0
|
|
clr.l (%a0)+
|
|
move.l %d0,%d1
|
|
lsr.l %d2,%d0
|
|
neg.w %d2
|
|
add.w #32,%d2
|
|
| Again, check to see if we shifted off any significant bits.
|
|
tst.l (%a0)
|
|
jeq 1f
|
|
bset #0,%d0 | Sticky bit.
|
|
1: move.l %d0,(%a0)
|
|
lsl.l %d2,%d1
|
|
jeq fp_nd_round
|
|
bset #0,%d0
|
|
jra fp_nd_round
|
|
| Sorry, the number is just too small.
|
|
2: clr.l (%a0)+
|
|
clr.l (%a0)
|
|
moveq #1,%d0 | Smallest possible fraction,
|
|
jra fp_nd_round | round as desired.
|
|
| zero and denormalized
|
|
fp_nd_zero:
|
|
tst.l (%a0)+
|
|
jne 1f
|
|
tst.l (%a0)
|
|
jne 1f
|
|
subq.l #8,%a0
|
|
printf PNORM,"%p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,")\n"
|
|
rts | zero. nothing to do.
|
|
| These are not merely subnormal numbers, but true denormals,
|
|
| i.e. pathologically small (exponent is 2**-16383) numbers.
|
|
| It is clearly impossible for even a normal extended number
|
|
| with that exponent to fit into double precision, so just
|
|
| write these ones off as "too darn small".
|
|
1: fp_set_sr FPSR_EXC_UNFL | Set UNFL bit
|
|
clr.l (%a0)
|
|
clr.l -(%a0)
|
|
move.w #0x3c01,-(%a0) | i.e. 2**-1022
|
|
addq.l #6,%a0
|
|
moveq #1,%d0
|
|
jra fp_nd_round | round.
|
|
| Exponent overflow. Just call it infinity.
|
|
fp_nd_large:
|
|
move.w #0x7ff,%d0
|
|
and.w (6,%a0),%d0
|
|
jeq 1f
|
|
fp_set_sr FPSR_EXC_INEX2
|
|
1: fp_set_sr FPSR_EXC_OVFL
|
|
move.w (FPD_RND,FPDATA),%d2
|
|
jne 3f | %d2 = 0 round to nearest
|
|
1: move.w #0x7fff,(-2,%a0)
|
|
clr.l (%a0)+
|
|
clr.l (%a0)
|
|
2: subq.l #8,%a0
|
|
printf PNORM,"%p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,")\n"
|
|
rts
|
|
3: subq.w #2,%d2
|
|
jcs 5f | %d2 < 2, round to zero
|
|
jhi 4f | %d2 > 2, round to +infinity
|
|
tst.b (-3,%a0) | to -inf
|
|
jne 1b
|
|
jra 5f
|
|
4: tst.b (-3,%a0) | to +inf
|
|
jeq 1b
|
|
5: move.w #0x43fe,(-2,%a0)
|
|
moveq #-1,%d0
|
|
move.l %d0,(%a0)+
|
|
move.w #0xf800,%d0
|
|
move.l %d0,(%a0)
|
|
jra 2b
|
|
| Infinities or NaNs
|
|
fp_nd_huge:
|
|
subq.l #4,%a0
|
|
printf PNORM,"%p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,")\n"
|
|
rts
|
|
|
|
| fp_normalize_single:
|
|
| normalize an extended with single (23-bit) precision
|
|
| args: %a0 (struct fp_ext *)
|
|
|
|
fp_normalize_single:
|
|
printf PNORM,"ns: %p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,") "
|
|
addq.l #2,%a0
|
|
move.w (%a0)+,%d2
|
|
jeq fp_ns_zero | zero / denormalized
|
|
cmp.w #0x7fff,%d2
|
|
jeq fp_ns_huge | NaN / infinitive.
|
|
sub.w #0x4000-0x7f,%d2 | will the exponent fit?
|
|
jcs fp_ns_small | too small.
|
|
cmp.w #0xfe,%d2
|
|
jcc fp_ns_large | too big.
|
|
move.l (%a0)+,%d0 | get high lword of mantissa
|
|
fp_ns_round:
|
|
tst.l (%a0) | check the low lword
|
|
jeq 1f
|
|
| Set a sticky bit if it is non-zero. This should only
|
|
| affect the rounding in what would otherwise be equal-
|
|
| distance situations, which is what we want it to do.
|
|
bset #0,%d0
|
|
1: clr.l (%a0) | zap it from memory.
|
|
| now, round off the low 8 bits of the hi lword.
|
|
tst.b %d0 | 8 low bits.
|
|
jne fp_ns_checkround | Are they non-zero?
|
|
| nothing to do here
|
|
subq.l #8,%a0
|
|
printf PNORM,"%p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,")\n"
|
|
rts
|
|
fp_ns_checkround:
|
|
fp_set_sr FPSR_EXC_INEX2 | INEX2 bit
|
|
clr.b -(%a0) | clear low byte of high lword
|
|
subq.l #3,%a0
|
|
move.w (FPD_RND,FPDATA),%d2 | rounding mode
|
|
jne 2f | %d2 == 0, round to nearest
|
|
tst.b %d0 | test guard bit
|
|
jpl 9f | zero is closer
|
|
btst #8,%d0 | test lsb bit
|
|
| round to even behaviour, see above.
|
|
jne fp_ns_doroundup | round to infinity
|
|
lsl.b #1,%d0 | check low bits
|
|
jeq 9f | round to zero
|
|
fp_ns_doroundup:
|
|
| round (the mantissa, that is) towards infinity
|
|
add.l #0x100,(%a0)
|
|
jcc 9f | no overflow, good.
|
|
| Overflow. This means that the %d1 was 0xffffff00, so it
|
|
| is now zero. We will set the mantissa to reflect this, and
|
|
| increment the exponent (checking for overflow there too)
|
|
move.w #0x8000,(%a0)
|
|
addq.w #1,-(%a0)
|
|
cmp.w #0x407f,(%a0)+ | exponent now overflown?
|
|
jeq fp_ns_large | yes, so make it infinity.
|
|
9: subq.l #4,%a0
|
|
printf PNORM,"%p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,")\n"
|
|
rts
|
|
| check nondefault rounding modes
|
|
2: subq.w #2,%d2
|
|
jcs 9b | %d2 < 2, round to zero
|
|
jhi 3f | %d2 > 2, round to +infinity
|
|
tst.b (-3,%a0) | to -inf
|
|
jne fp_ns_doroundup | negative, round to infinity
|
|
jra 9b | positive, round to zero
|
|
3: tst.b (-3,%a0) | to +inf
|
|
jeq fp_ns_doroundup | positive, round to infinity
|
|
jra 9b | negative, round to zero
|
|
| Exponent underflow. Try to make a denormal, and set it to
|
|
| the smallest possible fraction if this fails.
|
|
fp_ns_small:
|
|
fp_set_sr FPSR_EXC_UNFL | set UNFL bit
|
|
move.w #0x3f81,(-2,%a0) | 2**-126
|
|
neg.w %d2 | degree of underflow
|
|
cmp.w #32,%d2 | single or double shift?
|
|
jcc 2f
|
|
| a 32-bit shift.
|
|
move.l (%a0),%d0
|
|
move.l %d0,%d1
|
|
lsr.l %d2,%d0
|
|
move.l %d0,(%a0)+
|
|
| Check to see if we shifted off any significant bits.
|
|
neg.w %d2
|
|
add.w #32,%d2
|
|
lsl.l %d2,%d1
|
|
jeq 1f
|
|
bset #0,%d0 | Sticky bit.
|
|
| Check the lower lword
|
|
1: tst.l (%a0)
|
|
jeq fp_ns_round
|
|
clr (%a0)
|
|
bset #0,%d0 | Sticky bit.
|
|
jra fp_ns_round
|
|
| Sorry, the number is just too small.
|
|
2: clr.l (%a0)+
|
|
clr.l (%a0)
|
|
moveq #1,%d0 | Smallest possible fraction,
|
|
jra fp_ns_round | round as desired.
|
|
| Exponent overflow. Just call it infinity.
|
|
fp_ns_large:
|
|
tst.b (3,%a0)
|
|
jeq 1f
|
|
fp_set_sr FPSR_EXC_INEX2
|
|
1: fp_set_sr FPSR_EXC_OVFL
|
|
move.w (FPD_RND,FPDATA),%d2
|
|
jne 3f | %d2 = 0 round to nearest
|
|
1: move.w #0x7fff,(-2,%a0)
|
|
clr.l (%a0)+
|
|
clr.l (%a0)
|
|
2: subq.l #8,%a0
|
|
printf PNORM,"%p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,")\n"
|
|
rts
|
|
3: subq.w #2,%d2
|
|
jcs 5f | %d2 < 2, round to zero
|
|
jhi 4f | %d2 > 2, round to +infinity
|
|
tst.b (-3,%a0) | to -inf
|
|
jne 1b
|
|
jra 5f
|
|
4: tst.b (-3,%a0) | to +inf
|
|
jeq 1b
|
|
5: move.w #0x407e,(-2,%a0)
|
|
move.l #0xffffff00,(%a0)+
|
|
clr.l (%a0)
|
|
jra 2b
|
|
| zero and denormalized
|
|
fp_ns_zero:
|
|
tst.l (%a0)+
|
|
jne 1f
|
|
tst.l (%a0)
|
|
jne 1f
|
|
subq.l #8,%a0
|
|
printf PNORM,"%p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,")\n"
|
|
rts | zero. nothing to do.
|
|
| These are not merely subnormal numbers, but true denormals,
|
|
| i.e. pathologically small (exponent is 2**-16383) numbers.
|
|
| It is clearly impossible for even a normal extended number
|
|
| with that exponent to fit into single precision, so just
|
|
| write these ones off as "too darn small".
|
|
1: fp_set_sr FPSR_EXC_UNFL | Set UNFL bit
|
|
clr.l (%a0)
|
|
clr.l -(%a0)
|
|
move.w #0x3f81,-(%a0) | i.e. 2**-126
|
|
addq.l #6,%a0
|
|
moveq #1,%d0
|
|
jra fp_ns_round | round.
|
|
| Infinities or NaNs
|
|
fp_ns_huge:
|
|
subq.l #4,%a0
|
|
printf PNORM,"%p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,")\n"
|
|
rts
|
|
|
|
| fp_normalize_single_fast:
|
|
| normalize an extended with single (23-bit) precision
|
|
| this is only used by fsgldiv/fsgdlmul, where the
|
|
| operand is not completly normalized.
|
|
| args: %a0 (struct fp_ext *)
|
|
|
|
fp_normalize_single_fast:
|
|
printf PNORM,"nsf: %p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,") "
|
|
addq.l #2,%a0
|
|
move.w (%a0)+,%d2
|
|
cmp.w #0x7fff,%d2
|
|
jeq fp_nsf_huge | NaN / infinitive.
|
|
move.l (%a0)+,%d0 | get high lword of mantissa
|
|
fp_nsf_round:
|
|
tst.l (%a0) | check the low lword
|
|
jeq 1f
|
|
| Set a sticky bit if it is non-zero. This should only
|
|
| affect the rounding in what would otherwise be equal-
|
|
| distance situations, which is what we want it to do.
|
|
bset #0,%d0
|
|
1: clr.l (%a0) | zap it from memory.
|
|
| now, round off the low 8 bits of the hi lword.
|
|
tst.b %d0 | 8 low bits.
|
|
jne fp_nsf_checkround | Are they non-zero?
|
|
| nothing to do here
|
|
subq.l #8,%a0
|
|
printf PNORM,"%p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,")\n"
|
|
rts
|
|
fp_nsf_checkround:
|
|
fp_set_sr FPSR_EXC_INEX2 | INEX2 bit
|
|
clr.b -(%a0) | clear low byte of high lword
|
|
subq.l #3,%a0
|
|
move.w (FPD_RND,FPDATA),%d2 | rounding mode
|
|
jne 2f | %d2 == 0, round to nearest
|
|
tst.b %d0 | test guard bit
|
|
jpl 9f | zero is closer
|
|
btst #8,%d0 | test lsb bit
|
|
| round to even behaviour, see above.
|
|
jne fp_nsf_doroundup | round to infinity
|
|
lsl.b #1,%d0 | check low bits
|
|
jeq 9f | round to zero
|
|
fp_nsf_doroundup:
|
|
| round (the mantissa, that is) towards infinity
|
|
add.l #0x100,(%a0)
|
|
jcc 9f | no overflow, good.
|
|
| Overflow. This means that the %d1 was 0xffffff00, so it
|
|
| is now zero. We will set the mantissa to reflect this, and
|
|
| increment the exponent (checking for overflow there too)
|
|
move.w #0x8000,(%a0)
|
|
addq.w #1,-(%a0)
|
|
cmp.w #0x407f,(%a0)+ | exponent now overflown?
|
|
jeq fp_nsf_large | yes, so make it infinity.
|
|
9: subq.l #4,%a0
|
|
printf PNORM,"%p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,")\n"
|
|
rts
|
|
| check nondefault rounding modes
|
|
2: subq.w #2,%d2
|
|
jcs 9b | %d2 < 2, round to zero
|
|
jhi 3f | %d2 > 2, round to +infinity
|
|
tst.b (-3,%a0) | to -inf
|
|
jne fp_nsf_doroundup | negative, round to infinity
|
|
jra 9b | positive, round to zero
|
|
3: tst.b (-3,%a0) | to +inf
|
|
jeq fp_nsf_doroundup | positive, round to infinity
|
|
jra 9b | negative, round to zero
|
|
| Exponent overflow. Just call it infinity.
|
|
fp_nsf_large:
|
|
tst.b (3,%a0)
|
|
jeq 1f
|
|
fp_set_sr FPSR_EXC_INEX2
|
|
1: fp_set_sr FPSR_EXC_OVFL
|
|
move.w (FPD_RND,FPDATA),%d2
|
|
jne 3f | %d2 = 0 round to nearest
|
|
1: move.w #0x7fff,(-2,%a0)
|
|
clr.l (%a0)+
|
|
clr.l (%a0)
|
|
2: subq.l #8,%a0
|
|
printf PNORM,"%p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,")\n"
|
|
rts
|
|
3: subq.w #2,%d2
|
|
jcs 5f | %d2 < 2, round to zero
|
|
jhi 4f | %d2 > 2, round to +infinity
|
|
tst.b (-3,%a0) | to -inf
|
|
jne 1b
|
|
jra 5f
|
|
4: tst.b (-3,%a0) | to +inf
|
|
jeq 1b
|
|
5: move.w #0x407e,(-2,%a0)
|
|
move.l #0xffffff00,(%a0)+
|
|
clr.l (%a0)
|
|
jra 2b
|
|
| Infinities or NaNs
|
|
fp_nsf_huge:
|
|
subq.l #4,%a0
|
|
printf PNORM,"%p(",1,%a0
|
|
printx PNORM,%a0@
|
|
printf PNORM,")\n"
|
|
rts
|
|
|
|
| conv_ext2int (macro):
|
|
| Generates a subroutine that converts an extended value to an
|
|
| integer of a given size, again, with the appropriate type of
|
|
| rounding.
|
|
|
|
| Macro arguments:
|
|
| s: size, as given in an assembly instruction.
|
|
| b: number of bits in that size.
|
|
|
|
| Subroutine arguments:
|
|
| %a0: source (struct fp_ext *)
|
|
|
|
| Returns the integer in %d0 (like it should)
|
|
|
|
.macro conv_ext2int s,b
|
|
.set inf,(1<<(\b-1))-1 | i.e. MAXINT
|
|
printf PCONV,"e2i%d: %p(",2,#\b,%a0
|
|
printx PCONV,%a0@
|
|
printf PCONV,") "
|
|
addq.l #2,%a0
|
|
move.w (%a0)+,%d2 | exponent
|
|
jeq fp_e2i_zero\b | zero / denorm (== 0, here)
|
|
cmp.w #0x7fff,%d2
|
|
jeq fp_e2i_huge\b | Inf / NaN
|
|
sub.w #0x3ffe,%d2
|
|
jcs fp_e2i_small\b
|
|
cmp.w #\b,%d2
|
|
jhi fp_e2i_large\b
|
|
move.l (%a0),%d0
|
|
move.l %d0,%d1
|
|
lsl.l %d2,%d1
|
|
jne fp_e2i_round\b
|
|
tst.l (4,%a0)
|
|
jne fp_e2i_round\b
|
|
neg.w %d2
|
|
add.w #32,%d2
|
|
lsr.l %d2,%d0
|
|
9: tst.w (-4,%a0)
|
|
jne 1f
|
|
tst.\s %d0
|
|
jmi fp_e2i_large\b
|
|
printf PCONV,"-> %p\n",1,%d0
|
|
rts
|
|
1: neg.\s %d0
|
|
jeq 1f
|
|
jpl fp_e2i_large\b
|
|
1: printf PCONV,"-> %p\n",1,%d0
|
|
rts
|
|
fp_e2i_round\b:
|
|
fp_set_sr FPSR_EXC_INEX2 | INEX2 bit
|
|
neg.w %d2
|
|
add.w #32,%d2
|
|
.if \b>16
|
|
jeq 5f
|
|
.endif
|
|
lsr.l %d2,%d0
|
|
move.w (FPD_RND,FPDATA),%d2 | rounding mode
|
|
jne 2f | %d2 == 0, round to nearest
|
|
tst.l %d1 | test guard bit
|
|
jpl 9b | zero is closer
|
|
btst %d2,%d0 | test lsb bit (%d2 still 0)
|
|
jne fp_e2i_doroundup\b
|
|
lsl.l #1,%d1 | check low bits
|
|
jne fp_e2i_doroundup\b
|
|
tst.l (4,%a0)
|
|
jeq 9b
|
|
fp_e2i_doroundup\b:
|
|
addq.l #1,%d0
|
|
jra 9b
|
|
| check nondefault rounding modes
|
|
2: subq.w #2,%d2
|
|
jcs 9b | %d2 < 2, round to zero
|
|
jhi 3f | %d2 > 2, round to +infinity
|
|
tst.w (-4,%a0) | to -inf
|
|
jne fp_e2i_doroundup\b | negative, round to infinity
|
|
jra 9b | positive, round to zero
|
|
3: tst.w (-4,%a0) | to +inf
|
|
jeq fp_e2i_doroundup\b | positive, round to infinity
|
|
jra 9b | negative, round to zero
|
|
| we are only want -2**127 get correctly rounded here,
|
|
| since the guard bit is in the lower lword.
|
|
| everything else ends up anyway as overflow.
|
|
.if \b>16
|
|
5: move.w (FPD_RND,FPDATA),%d2 | rounding mode
|
|
jne 2b | %d2 == 0, round to nearest
|
|
move.l (4,%a0),%d1 | test guard bit
|
|
jpl 9b | zero is closer
|
|
lsl.l #1,%d1 | check low bits
|
|
jne fp_e2i_doroundup\b
|
|
jra 9b
|
|
.endif
|
|
fp_e2i_zero\b:
|
|
clr.l %d0
|
|
tst.l (%a0)+
|
|
jne 1f
|
|
tst.l (%a0)
|
|
jeq 3f
|
|
1: subq.l #4,%a0
|
|
fp_clr_sr FPSR_EXC_UNFL | fp_normalize_ext has set this bit
|
|
fp_e2i_small\b:
|
|
fp_set_sr FPSR_EXC_INEX2
|
|
clr.l %d0
|
|
move.w (FPD_RND,FPDATA),%d2 | rounding mode
|
|
subq.w #2,%d2
|
|
jcs 3f | %d2 < 2, round to nearest/zero
|
|
jhi 2f | %d2 > 2, round to +infinity
|
|
tst.w (-4,%a0) | to -inf
|
|
jeq 3f
|
|
subq.\s #1,%d0
|
|
jra 3f
|
|
2: tst.w (-4,%a0) | to +inf
|
|
jne 3f
|
|
addq.\s #1,%d0
|
|
3: printf PCONV,"-> %p\n",1,%d0
|
|
rts
|
|
fp_e2i_large\b:
|
|
fp_set_sr FPSR_EXC_OPERR
|
|
move.\s #inf,%d0
|
|
tst.w (-4,%a0)
|
|
jeq 1f
|
|
addq.\s #1,%d0
|
|
1: printf PCONV,"-> %p\n",1,%d0
|
|
rts
|
|
fp_e2i_huge\b:
|
|
move.\s (%a0),%d0
|
|
tst.l (%a0)
|
|
jne 1f
|
|
tst.l (%a0)
|
|
jeq fp_e2i_large\b
|
|
| fp_normalize_ext has set this bit already
|
|
| and made the number nonsignaling
|
|
1: fp_tst_sr FPSR_EXC_SNAN
|
|
jne 1f
|
|
fp_set_sr FPSR_EXC_OPERR
|
|
1: printf PCONV,"-> %p\n",1,%d0
|
|
rts
|
|
.endm
|
|
|
|
fp_conv_ext2long:
|
|
conv_ext2int l,32
|
|
|
|
fp_conv_ext2short:
|
|
conv_ext2int w,16
|
|
|
|
fp_conv_ext2byte:
|
|
conv_ext2int b,8
|
|
|
|
fp_conv_ext2double:
|
|
jsr fp_normalize_double
|
|
printf PCONV,"e2d: %p(",1,%a0
|
|
printx PCONV,%a0@
|
|
printf PCONV,"), "
|
|
move.l (%a0)+,%d2
|
|
cmp.w #0x7fff,%d2
|
|
jne 1f
|
|
move.w #0x7ff,%d2
|
|
move.l (%a0)+,%d0
|
|
jra 2f
|
|
1: sub.w #0x3fff-0x3ff,%d2
|
|
move.l (%a0)+,%d0
|
|
jmi 2f
|
|
clr.w %d2
|
|
2: lsl.w #5,%d2
|
|
lsl.l #7,%d2
|
|
lsl.l #8,%d2
|
|
move.l %d0,%d1
|
|
lsl.l #1,%d0
|
|
lsr.l #4,%d0
|
|
lsr.l #8,%d0
|
|
or.l %d2,%d0
|
|
putuser.l %d0,(%a1)+,fp_err_ua2,%a1
|
|
moveq #21,%d0
|
|
lsl.l %d0,%d1
|
|
move.l (%a0),%d0
|
|
lsr.l #4,%d0
|
|
lsr.l #7,%d0
|
|
or.l %d1,%d0
|
|
putuser.l %d0,(%a1),fp_err_ua2,%a1
|
|
#ifdef FPU_EMU_DEBUG
|
|
getuser.l %a1@(-4),%d0,fp_err_ua2,%a1
|
|
getuser.l %a1@(0),%d1,fp_err_ua2,%a1
|
|
printf PCONV,"%p(%08x%08x)\n",3,%a1,%d0,%d1
|
|
#endif
|
|
rts
|
|
|
|
fp_conv_ext2single:
|
|
jsr fp_normalize_single
|
|
printf PCONV,"e2s: %p(",1,%a0
|
|
printx PCONV,%a0@
|
|
printf PCONV,"), "
|
|
move.l (%a0)+,%d1
|
|
cmp.w #0x7fff,%d1
|
|
jne 1f
|
|
move.w #0xff,%d1
|
|
move.l (%a0)+,%d0
|
|
jra 2f
|
|
1: sub.w #0x3fff-0x7f,%d1
|
|
move.l (%a0)+,%d0
|
|
jmi 2f
|
|
clr.w %d1
|
|
2: lsl.w #8,%d1
|
|
lsl.l #7,%d1
|
|
lsl.l #8,%d1
|
|
bclr #31,%d0
|
|
lsr.l #8,%d0
|
|
or.l %d1,%d0
|
|
printf PCONV,"%08x\n",1,%d0
|
|
rts
|
|
|
|
| special return addresses for instr that
|
|
| encode the rounding precision in the opcode
|
|
| (e.g. fsmove,fdmove)
|
|
|
|
fp_finalrounding_single:
|
|
addq.l #8,%sp
|
|
jsr fp_normalize_ext
|
|
jsr fp_normalize_single
|
|
jra fp_finaltest
|
|
|
|
fp_finalrounding_single_fast:
|
|
addq.l #8,%sp
|
|
jsr fp_normalize_ext
|
|
jsr fp_normalize_single_fast
|
|
jra fp_finaltest
|
|
|
|
fp_finalrounding_double:
|
|
addq.l #8,%sp
|
|
jsr fp_normalize_ext
|
|
jsr fp_normalize_double
|
|
jra fp_finaltest
|
|
|
|
| fp_finaltest:
|
|
| set the emulated status register based on the outcome of an
|
|
| emulated instruction.
|
|
|
|
fp_finalrounding:
|
|
addq.l #8,%sp
|
|
| printf ,"f: %p\n",1,%a0
|
|
jsr fp_normalize_ext
|
|
move.w (FPD_PREC,FPDATA),%d0
|
|
subq.w #1,%d0
|
|
jcs fp_finaltest
|
|
jne 1f
|
|
jsr fp_normalize_single
|
|
jra 2f
|
|
1: jsr fp_normalize_double
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2:| printf ,"f: %p\n",1,%a0
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fp_finaltest:
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| First, we do some of the obvious tests for the exception
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| status byte and condition code bytes of fp_sr here, so that
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| they do not have to be handled individually by every
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| emulated instruction.
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clr.l %d0
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addq.l #1,%a0
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tst.b (%a0)+ | sign
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jeq 1f
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bset #FPSR_CC_NEG-24,%d0 | N bit
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1: cmp.w #0x7fff,(%a0)+ | exponent
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jeq 2f
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| test for zero
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moveq #FPSR_CC_Z-24,%d1
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tst.l (%a0)+
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jne 9f
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tst.l (%a0)
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jne 9f
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jra 8f
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| infinitiv and NAN
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2: moveq #FPSR_CC_NAN-24,%d1
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move.l (%a0)+,%d2
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lsl.l #1,%d2 | ignore high bit
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jne 8f
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tst.l (%a0)
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jne 8f
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moveq #FPSR_CC_INF-24,%d1
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8: bset %d1,%d0
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9: move.b %d0,(FPD_FPSR+0,FPDATA) | set condition test result
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| move instructions enter here
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| Here, we test things in the exception status byte, and set
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| other things in the accrued exception byte accordingly.
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| Emulated instructions can set various things in the former,
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| as defined in fp_emu.h.
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fp_final:
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move.l (FPD_FPSR,FPDATA),%d0
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#if 0
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btst #FPSR_EXC_SNAN,%d0 | EXC_SNAN
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jne 1f
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btst #FPSR_EXC_OPERR,%d0 | EXC_OPERR
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jeq 2f
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1: bset #FPSR_AEXC_IOP,%d0 | set IOP bit
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2: btst #FPSR_EXC_OVFL,%d0 | EXC_OVFL
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jeq 1f
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bset #FPSR_AEXC_OVFL,%d0 | set OVFL bit
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1: btst #FPSR_EXC_UNFL,%d0 | EXC_UNFL
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jeq 1f
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btst #FPSR_EXC_INEX2,%d0 | EXC_INEX2
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jeq 1f
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bset #FPSR_AEXC_UNFL,%d0 | set UNFL bit
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1: btst #FPSR_EXC_DZ,%d0 | EXC_INEX1
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jeq 1f
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bset #FPSR_AEXC_DZ,%d0 | set DZ bit
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1: btst #FPSR_EXC_OVFL,%d0 | EXC_OVFL
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jne 1f
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btst #FPSR_EXC_INEX2,%d0 | EXC_INEX2
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jne 1f
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btst #FPSR_EXC_INEX1,%d0 | EXC_INEX1
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jeq 2f
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1: bset #FPSR_AEXC_INEX,%d0 | set INEX bit
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2: move.l %d0,(FPD_FPSR,FPDATA)
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#else
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| same as above, greatly optimized, but untested (yet)
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move.l %d0,%d2
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lsr.l #5,%d0
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move.l %d0,%d1
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lsr.l #4,%d1
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or.l %d0,%d1
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and.b #0x08,%d1
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move.l %d2,%d0
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lsr.l #6,%d0
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or.l %d1,%d0
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move.l %d2,%d1
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lsr.l #4,%d1
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or.b #0xdf,%d1
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and.b %d1,%d0
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move.l %d2,%d1
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lsr.l #7,%d1
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and.b #0x80,%d1
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or.b %d1,%d0
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and.b #0xf8,%d0
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or.b %d0,%d2
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move.l %d2,(FPD_FPSR,FPDATA)
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#endif
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move.b (FPD_FPSR+2,FPDATA),%d0
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and.b (FPD_FPCR+2,FPDATA),%d0
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jeq 1f
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printf ,"send signal!!!\n"
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1: jra fp_end
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