diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/sh/kernel/cpu/sh4/fpu.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/sh/kernel/cpu/sh4/fpu.c')
-rw-r--r-- | arch/sh/kernel/cpu/sh4/fpu.c | 335 |
1 files changed, 335 insertions, 0 deletions
diff --git a/arch/sh/kernel/cpu/sh4/fpu.c b/arch/sh/kernel/cpu/sh4/fpu.c new file mode 100644 index 00000000000..f486c07e10e --- /dev/null +++ b/arch/sh/kernel/cpu/sh4/fpu.c @@ -0,0 +1,335 @@ +/* $Id: fpu.c,v 1.4 2004/01/13 05:52:11 kkojima Exp $ + * + * linux/arch/sh/kernel/fpu.c + * + * Save/restore floating point context for signal handlers. + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 1999, 2000 Kaz Kojima & Niibe Yutaka + * + * FIXME! These routines can be optimized in big endian case. + */ + +#include <linux/sched.h> +#include <linux/signal.h> +#include <asm/processor.h> +#include <asm/io.h> + +/* The PR (precision) bit in the FP Status Register must be clear when + * an frchg instruction is executed, otherwise the instruction is undefined. + * Executing frchg with PR set causes a trap on some SH4 implementations. + */ + +#define FPSCR_RCHG 0x00000000 + + +/* + * Save FPU registers onto task structure. + * Assume called with FPU enabled (SR.FD=0). + */ +void +save_fpu(struct task_struct *tsk, struct pt_regs *regs) +{ + unsigned long dummy; + + clear_tsk_thread_flag(tsk, TIF_USEDFPU); + enable_fpu(); + asm volatile("sts.l fpul, @-%0\n\t" + "sts.l fpscr, @-%0\n\t" + "lds %2, fpscr\n\t" + "frchg\n\t" + "fmov.s fr15, @-%0\n\t" + "fmov.s fr14, @-%0\n\t" + "fmov.s fr13, @-%0\n\t" + "fmov.s fr12, @-%0\n\t" + "fmov.s fr11, @-%0\n\t" + "fmov.s fr10, @-%0\n\t" + "fmov.s fr9, @-%0\n\t" + "fmov.s fr8, @-%0\n\t" + "fmov.s fr7, @-%0\n\t" + "fmov.s fr6, @-%0\n\t" + "fmov.s fr5, @-%0\n\t" + "fmov.s fr4, @-%0\n\t" + "fmov.s fr3, @-%0\n\t" + "fmov.s fr2, @-%0\n\t" + "fmov.s fr1, @-%0\n\t" + "fmov.s fr0, @-%0\n\t" + "frchg\n\t" + "fmov.s fr15, @-%0\n\t" + "fmov.s fr14, @-%0\n\t" + "fmov.s fr13, @-%0\n\t" + "fmov.s fr12, @-%0\n\t" + "fmov.s fr11, @-%0\n\t" + "fmov.s fr10, @-%0\n\t" + "fmov.s fr9, @-%0\n\t" + "fmov.s fr8, @-%0\n\t" + "fmov.s fr7, @-%0\n\t" + "fmov.s fr6, @-%0\n\t" + "fmov.s fr5, @-%0\n\t" + "fmov.s fr4, @-%0\n\t" + "fmov.s fr3, @-%0\n\t" + "fmov.s fr2, @-%0\n\t" + "fmov.s fr1, @-%0\n\t" + "fmov.s fr0, @-%0\n\t" + "lds %3, fpscr\n\t" + : "=r" (dummy) + : "0" ((char *)(&tsk->thread.fpu.hard.status)), + "r" (FPSCR_RCHG), + "r" (FPSCR_INIT) + : "memory"); + + disable_fpu(); + release_fpu(regs); +} + +static void +restore_fpu(struct task_struct *tsk) +{ + unsigned long dummy; + + enable_fpu(); + asm volatile("lds %2, fpscr\n\t" + "fmov.s @%0+, fr0\n\t" + "fmov.s @%0+, fr1\n\t" + "fmov.s @%0+, fr2\n\t" + "fmov.s @%0+, fr3\n\t" + "fmov.s @%0+, fr4\n\t" + "fmov.s @%0+, fr5\n\t" + "fmov.s @%0+, fr6\n\t" + "fmov.s @%0+, fr7\n\t" + "fmov.s @%0+, fr8\n\t" + "fmov.s @%0+, fr9\n\t" + "fmov.s @%0+, fr10\n\t" + "fmov.s @%0+, fr11\n\t" + "fmov.s @%0+, fr12\n\t" + "fmov.s @%0+, fr13\n\t" + "fmov.s @%0+, fr14\n\t" + "fmov.s @%0+, fr15\n\t" + "frchg\n\t" + "fmov.s @%0+, fr0\n\t" + "fmov.s @%0+, fr1\n\t" + "fmov.s @%0+, fr2\n\t" + "fmov.s @%0+, fr3\n\t" + "fmov.s @%0+, fr4\n\t" + "fmov.s @%0+, fr5\n\t" + "fmov.s @%0+, fr6\n\t" + "fmov.s @%0+, fr7\n\t" + "fmov.s @%0+, fr8\n\t" + "fmov.s @%0+, fr9\n\t" + "fmov.s @%0+, fr10\n\t" + "fmov.s @%0+, fr11\n\t" + "fmov.s @%0+, fr12\n\t" + "fmov.s @%0+, fr13\n\t" + "fmov.s @%0+, fr14\n\t" + "fmov.s @%0+, fr15\n\t" + "frchg\n\t" + "lds.l @%0+, fpscr\n\t" + "lds.l @%0+, fpul\n\t" + : "=r" (dummy) + : "0" (&tsk->thread.fpu), "r" (FPSCR_RCHG) + : "memory"); + disable_fpu(); +} + +/* + * Load the FPU with signalling NANS. This bit pattern we're using + * has the property that no matter wether considered as single or as + * double precission represents signaling NANS. + */ + +static void +fpu_init(void) +{ + enable_fpu(); + asm volatile("lds %0, fpul\n\t" + "lds %1, fpscr\n\t" + "fsts fpul, fr0\n\t" + "fsts fpul, fr1\n\t" + "fsts fpul, fr2\n\t" + "fsts fpul, fr3\n\t" + "fsts fpul, fr4\n\t" + "fsts fpul, fr5\n\t" + "fsts fpul, fr6\n\t" + "fsts fpul, fr7\n\t" + "fsts fpul, fr8\n\t" + "fsts fpul, fr9\n\t" + "fsts fpul, fr10\n\t" + "fsts fpul, fr11\n\t" + "fsts fpul, fr12\n\t" + "fsts fpul, fr13\n\t" + "fsts fpul, fr14\n\t" + "fsts fpul, fr15\n\t" + "frchg\n\t" + "fsts fpul, fr0\n\t" + "fsts fpul, fr1\n\t" + "fsts fpul, fr2\n\t" + "fsts fpul, fr3\n\t" + "fsts fpul, fr4\n\t" + "fsts fpul, fr5\n\t" + "fsts fpul, fr6\n\t" + "fsts fpul, fr7\n\t" + "fsts fpul, fr8\n\t" + "fsts fpul, fr9\n\t" + "fsts fpul, fr10\n\t" + "fsts fpul, fr11\n\t" + "fsts fpul, fr12\n\t" + "fsts fpul, fr13\n\t" + "fsts fpul, fr14\n\t" + "fsts fpul, fr15\n\t" + "frchg\n\t" + "lds %2, fpscr\n\t" + : /* no output */ + : "r" (0), "r" (FPSCR_RCHG), "r" (FPSCR_INIT)); + disable_fpu(); +} + +/** + * denormal_to_double - Given denormalized float number, + * store double float + * + * @fpu: Pointer to sh_fpu_hard structure + * @n: Index to FP register + */ +static void +denormal_to_double (struct sh_fpu_hard_struct *fpu, int n) +{ + unsigned long du, dl; + unsigned long x = fpu->fpul; + int exp = 1023 - 126; + + if (x != 0 && (x & 0x7f800000) == 0) { + du = (x & 0x80000000); + while ((x & 0x00800000) == 0) { + x <<= 1; + exp--; + } + x &= 0x007fffff; + du |= (exp << 20) | (x >> 3); + dl = x << 29; + + fpu->fp_regs[n] = du; + fpu->fp_regs[n+1] = dl; + } +} + +/** + * ieee_fpe_handler - Handle denormalized number exception + * + * @regs: Pointer to register structure + * + * Returns 1 when it's handled (should not cause exception). + */ +static int +ieee_fpe_handler (struct pt_regs *regs) +{ + unsigned short insn = *(unsigned short *) regs->pc; + unsigned short finsn; + unsigned long nextpc; + int nib[4] = { + (insn >> 12) & 0xf, + (insn >> 8) & 0xf, + (insn >> 4) & 0xf, + insn & 0xf}; + + if (nib[0] == 0xb || + (nib[0] == 0x4 && nib[2] == 0x0 && nib[3] == 0xb)) /* bsr & jsr */ + regs->pr = regs->pc + 4; + + if (nib[0] == 0xa || nib[0] == 0xb) { /* bra & bsr */ + nextpc = regs->pc + 4 + ((short) ((insn & 0xfff) << 4) >> 3); + finsn = *(unsigned short *) (regs->pc + 2); + } else if (nib[0] == 0x8 && nib[1] == 0xd) { /* bt/s */ + if (regs->sr & 1) + nextpc = regs->pc + 4 + ((char) (insn & 0xff) << 1); + else + nextpc = regs->pc + 4; + finsn = *(unsigned short *) (regs->pc + 2); + } else if (nib[0] == 0x8 && nib[1] == 0xf) { /* bf/s */ + if (regs->sr & 1) + nextpc = regs->pc + 4; + else + nextpc = regs->pc + 4 + ((char) (insn & 0xff) << 1); + finsn = *(unsigned short *) (regs->pc + 2); + } else if (nib[0] == 0x4 && nib[3] == 0xb && + (nib[2] == 0x0 || nib[2] == 0x2)) { /* jmp & jsr */ + nextpc = regs->regs[nib[1]]; + finsn = *(unsigned short *) (regs->pc + 2); + } else if (nib[0] == 0x0 && nib[3] == 0x3 && + (nib[2] == 0x0 || nib[2] == 0x2)) { /* braf & bsrf */ + nextpc = regs->pc + 4 + regs->regs[nib[1]]; + finsn = *(unsigned short *) (regs->pc + 2); + } else if (insn == 0x000b) { /* rts */ + nextpc = regs->pr; + finsn = *(unsigned short *) (regs->pc + 2); + } else { + nextpc = regs->pc + 2; + finsn = insn; + } + + if ((finsn & 0xf1ff) == 0xf0ad) { /* fcnvsd */ + struct task_struct *tsk = current; + + save_fpu(tsk, regs); + if ((tsk->thread.fpu.hard.fpscr & (1 << 17))) { + /* FPU error */ + denormal_to_double (&tsk->thread.fpu.hard, + (finsn >> 8) & 0xf); + tsk->thread.fpu.hard.fpscr &= + ~(FPSCR_CAUSE_MASK | FPSCR_FLAG_MASK); + grab_fpu(regs); + restore_fpu(tsk); + set_tsk_thread_flag(tsk, TIF_USEDFPU); + } else { + tsk->thread.trap_no = 11; + tsk->thread.error_code = 0; + force_sig(SIGFPE, tsk); + } + + regs->pc = nextpc; + return 1; + } + + return 0; +} + +asmlinkage void +do_fpu_error(unsigned long r4, unsigned long r5, unsigned long r6, unsigned long r7, + struct pt_regs regs) +{ + struct task_struct *tsk = current; + + if (ieee_fpe_handler (®s)) + return; + + regs.pc += 2; + save_fpu(tsk, ®s); + tsk->thread.trap_no = 11; + tsk->thread.error_code = 0; + force_sig(SIGFPE, tsk); +} + +asmlinkage void +do_fpu_state_restore(unsigned long r4, unsigned long r5, unsigned long r6, + unsigned long r7, struct pt_regs regs) +{ + struct task_struct *tsk = current; + + grab_fpu(®s); + if (!user_mode(®s)) { + printk(KERN_ERR "BUG: FPU is used in kernel mode.\n"); + return; + } + + if (used_math()) { + /* Using the FPU again. */ + restore_fpu(tsk); + } else { + /* First time FPU user. */ + fpu_init(); + set_used_math(); + } + set_tsk_thread_flag(tsk, TIF_USEDFPU); +} |