76 lines
1.9 KiB
ArmAsm
76 lines
1.9 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0-or-later WITH GCC-exception-2.0 */
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#include <linux/linkage.h>
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#include <asm/asmmacro.h>
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#include <asm/core.h>
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ENTRY(__divsi3)
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abi_entry_default
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#if XCHAL_HAVE_DIV32
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quos a2, a2, a3
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#else
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xor a7, a2, a3 /* sign = dividend ^ divisor */
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do_abs a6, a2, a4 /* udividend = abs (dividend) */
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do_abs a3, a3, a4 /* udivisor = abs (divisor) */
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bltui a3, 2, .Lle_one /* check if udivisor <= 1 */
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do_nsau a5, a6, a2, a8 /* udividend_shift = nsau (udividend) */
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do_nsau a4, a3, a2, a8 /* udivisor_shift = nsau (udivisor) */
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bgeu a5, a4, .Lspecial
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sub a4, a4, a5 /* count = udivisor_shift - udividend_shift */
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ssl a4
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sll a3, a3 /* udivisor <<= count */
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movi a2, 0 /* quotient = 0 */
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/* test-subtract-and-shift loop; one quotient bit on each iteration */
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#if XCHAL_HAVE_LOOPS
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loopnez a4, .Lloopend
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#endif /* XCHAL_HAVE_LOOPS */
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.Lloop:
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bltu a6, a3, .Lzerobit
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sub a6, a6, a3
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addi a2, a2, 1
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.Lzerobit:
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slli a2, a2, 1
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srli a3, a3, 1
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#if !XCHAL_HAVE_LOOPS
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addi a4, a4, -1
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bnez a4, .Lloop
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#endif /* !XCHAL_HAVE_LOOPS */
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.Lloopend:
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bltu a6, a3, .Lreturn
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addi a2, a2, 1 /* increment if udividend >= udivisor */
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.Lreturn:
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neg a5, a2
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movltz a2, a5, a7 /* return (sign < 0) ? -quotient : quotient */
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abi_ret_default
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.Lle_one:
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beqz a3, .Lerror
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neg a2, a6 /* if udivisor == 1, then return... */
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movgez a2, a6, a7 /* (sign < 0) ? -udividend : udividend */
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abi_ret_default
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.Lspecial:
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bltu a6, a3, .Lreturn0 /* if dividend < divisor, return 0 */
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movi a2, 1
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movi a4, -1
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movltz a2, a4, a7 /* else return (sign < 0) ? -1 : 1 */
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abi_ret_default
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.Lerror:
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/* Divide by zero: Use an illegal instruction to force an exception.
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The subsequent "DIV0" string can be recognized by the exception
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handler to identify the real cause of the exception. */
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ill
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.ascii "DIV0"
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.Lreturn0:
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movi a2, 0
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#endif /* XCHAL_HAVE_DIV32 */
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abi_ret_default
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ENDPROC(__divsi3)
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EXPORT_SYMBOL(__divsi3)
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