driver.c
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/*
* Linux/PA-RISC Project (http://www.parisc-linux.org/)
*
* Floating-point emulation code
* Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* linux/arch/math-emu/driver.c.c
*
* decodes and dispatches unimplemented FPU instructions
*
* Copyright (C) 1999, 2000 Philipp Rumpf <prumpf@tux.org>
* Copyright (C) 2001 Hewlett-Packard <bame@debian.org>
*/
#include <linux/sched.h>
#include "float.h"
#include "math-emu.h"
#define fptpos 31
#define fpr1pos 10
#define extru(r,pos,len) (((r) >> (31-(pos))) & (( 1 << (len)) - 1))
#define FPUDEBUG 0
/* Format of the floating-point exception registers. */
struct exc_reg {
unsigned int exception : 6;
unsigned int ei : 26;
};
/* Macros for grabbing bits of the instruction format from the 'ei'
field above. */
/* Major opcode 0c and 0e */
#define FP0CE_UID(i) (((i) >> 6) & 3)
#define FP0CE_CLASS(i) (((i) >> 9) & 3)
#define FP0CE_SUBOP(i) (((i) >> 13) & 7)
#define FP0CE_SUBOP1(i) (((i) >> 15) & 7) /* Class 1 subopcode */
#define FP0C_FORMAT(i) (((i) >> 11) & 3)
#define FP0E_FORMAT(i) (((i) >> 11) & 1)
/* Major opcode 0c, uid 2 (performance monitoring) */
#define FPPM_SUBOP(i) (((i) >> 9) & 0x1f)
/* Major opcode 2e (fused operations). */
#define FP2E_SUBOP(i) (((i) >> 5) & 1)
#define FP2E_FORMAT(i) (((i) >> 11) & 1)
/* Major opcode 26 (FMPYSUB) */
/* Major opcode 06 (FMPYADD) */
#define FPx6_FORMAT(i) ((i) & 0x1f)
/* Flags and enable bits of the status word. */
#define FPSW_FLAGS(w) ((w) >> 27)
#define FPSW_ENABLE(w) ((w) & 0x1f)
#define FPSW_V (1<<4)
#define FPSW_Z (1<<3)
#define FPSW_O (1<<2)
#define FPSW_U (1<<1)
#define FPSW_I (1<<0)
/* Handle a floating point exception. Return zero if the faulting
instruction can be completed successfully. */
int
handle_fpe(struct pt_regs *regs)
{
extern void printbinary(unsigned long x, int nbits);
struct siginfo si;
unsigned int orig_sw, sw;
int signalcode;
/* need an intermediate copy of float regs because FPU emulation
* code expects an artificial last entry which contains zero
*
* also, the passed in fr registers contain one word that defines
* the fpu type. the fpu type information is constructed
* inside the emulation code
*/
__u64 frcopy[36];
memcpy(frcopy, regs->fr, sizeof regs->fr);
frcopy[32] = 0;
memcpy(&orig_sw, frcopy, sizeof(orig_sw));
if (FPUDEBUG) {
printk(KERN_DEBUG "FP VZOUICxxxxCQCQCQCQCQCRMxxTDVZOUI ->\n ");
printbinary(orig_sw, 32);
printk(KERN_DEBUG "\n");
}
signalcode = decode_fpu(frcopy, 0x666);
/* Status word = FR0L. */
memcpy(&sw, frcopy, sizeof(sw));
if (FPUDEBUG) {
printk(KERN_DEBUG "VZOUICxxxxCQCQCQCQCQCRMxxTDVZOUI decode_fpu returns %d|0x%x\n",
signalcode >> 24, signalcode & 0xffffff);
printbinary(sw, 32);
printk(KERN_DEBUG "\n");
}
memcpy(regs->fr, frcopy, sizeof regs->fr);
if (signalcode != 0) {
si.si_signo = signalcode >> 24;
si.si_errno = 0;
si.si_code = signalcode & 0xffffff;
si.si_addr = (void __user *) regs->iaoq[0];
force_sig_info(si.si_signo, &si, current);
return -1;
}
return signalcode ? -1 : 0;
}