183 lines
5.1 KiB
C
183 lines
5.1 KiB
C
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/*
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NetWinder Floating Point Emulator
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(c) Rebel.com, 1998-1999
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(c) Philip Blundell, 1998-1999
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Direct questions, comments to Scott Bambrough <scottb@netwinder.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "fpa11.h"
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#include <linux/module.h>
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#include <linux/version.h>
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#include <linux/config.h>
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/* XXX */
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#include <linux/errno.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/signal.h>
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#include <linux/sched.h>
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#include <linux/init.h>
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/* XXX */
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#include "softfloat.h"
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#include "fpopcode.h"
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#include "fpmodule.h"
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#include "fpa11.inl"
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/* kernel symbols required for signal handling */
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typedef struct task_struct* PTASK;
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#ifdef MODULE
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void fp_send_sig(unsigned long sig, PTASK p, int priv);
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#if LINUX_VERSION_CODE > 0x20115
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MODULE_AUTHOR("Scott Bambrough <scottb@rebel.com>");
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MODULE_DESCRIPTION("NWFPE floating point emulator");
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#endif
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#else
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#define fp_send_sig send_sig
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#define kern_fp_enter fp_enter
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extern char fpe_type[];
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#endif
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/* kernel function prototypes required */
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void fp_setup(void);
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/* external declarations for saved kernel symbols */
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extern void (*kern_fp_enter)(void);
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/* Original value of fp_enter from kernel before patched by fpe_init. */
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static void (*orig_fp_enter)(void);
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/* forward declarations */
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extern void nwfpe_enter(void);
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#ifdef MODULE
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/*
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* Return 0 if we can be unloaded. This can only happen if
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* kern_fp_enter is still pointing at nwfpe_enter
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*/
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static int fpe_unload(void)
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{
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return (kern_fp_enter == nwfpe_enter) ? 0 : 1;
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}
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#endif
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static int __init fpe_init(void)
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{
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if (sizeof(FPA11) > sizeof(union fp_state)) {
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printk(KERN_ERR "nwfpe: bad structure size\n");
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return -EINVAL;
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}
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if (sizeof(FPREG) != 12) {
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printk(KERN_ERR "nwfpe: bad register size\n");
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return -EINVAL;
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}
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#ifdef MODULE
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if (!mod_member_present(&__this_module, can_unload))
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return -EINVAL;
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__this_module.can_unload = fpe_unload;
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#else
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if (fpe_type[0] && strcmp(fpe_type, "nwfpe"))
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return 0;
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#endif
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/* Display title, version and copyright information. */
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printk(KERN_WARNING "NetWinder Floating Point Emulator V0.95 "
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"(c) 1998-1999 Rebel.com\n");
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/* Save pointer to the old FP handler and then patch ourselves in */
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orig_fp_enter = kern_fp_enter;
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kern_fp_enter = nwfpe_enter;
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return 0;
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}
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static void __exit fpe_exit(void)
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{
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/* Restore the values we saved earlier. */
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kern_fp_enter = orig_fp_enter;
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}
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/*
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ScottB: November 4, 1998
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Moved this function out of softfloat-specialize into fpmodule.c.
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This effectively isolates all the changes required for integrating with the
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Linux kernel into fpmodule.c. Porting to NetBSD should only require modifying
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fpmodule.c to integrate with the NetBSD kernel (I hope!).
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[1/1/99: Not quite true any more unfortunately. There is Linux-specific
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code to access data in user space in some other source files at the
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moment (grep for get_user / put_user calls). --philb]
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float_exception_flags is a global variable in SoftFloat.
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This function is called by the SoftFloat routines to raise a floating
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point exception. We check the trap enable byte in the FPSR, and raise
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a SIGFPE exception if necessary. If not the relevant bits in the
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cumulative exceptions flag byte are set and we return.
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*/
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void float_raise(signed char flags)
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{
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register unsigned int fpsr, cumulativeTraps;
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#ifdef CONFIG_DEBUG_USER
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printk(KERN_DEBUG "NWFPE: %s[%d] takes exception %08x at %p from %08x\n",
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current->comm, current->pid, flags,
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__builtin_return_address(0), GET_USERREG()[15]);
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#endif
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/* Keep SoftFloat exception flags up to date. */
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float_exception_flags |= flags;
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/* Read fpsr and initialize the cumulativeTraps. */
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fpsr = readFPSR();
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cumulativeTraps = 0;
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/* For each type of exception, the cumulative trap exception bit is only
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set if the corresponding trap enable bit is not set. */
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if ((!(fpsr & BIT_IXE)) && (flags & BIT_IXC))
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cumulativeTraps |= BIT_IXC;
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if ((!(fpsr & BIT_UFE)) && (flags & BIT_UFC))
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cumulativeTraps |= BIT_UFC;
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if ((!(fpsr & BIT_OFE)) && (flags & BIT_OFC))
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cumulativeTraps |= BIT_OFC;
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if ((!(fpsr & BIT_DZE)) && (flags & BIT_DZC))
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cumulativeTraps |= BIT_DZC;
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if ((!(fpsr & BIT_IOE)) && (flags & BIT_IOC))
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cumulativeTraps |= BIT_IOC;
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/* Set the cumulative exceptions flags. */
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if (cumulativeTraps)
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writeFPSR(fpsr | cumulativeTraps);
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/* Raise an exception if necessary. */
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if (fpsr & (flags << 16))
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fp_send_sig(SIGFPE, current, 1);
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}
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module_init(fpe_init);
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module_exit(fpe_exit);
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