diff options
author | Paul Mundt <lethal@linux-sh.org> | 2007-11-26 20:38:36 +0900 |
---|---|---|
committer | Paul Mundt <lethal@linux-sh.org> | 2008-01-28 13:18:57 +0900 |
commit | 74d99a5e262229ee865f6f68528d10b82471ead6 (patch) | |
tree | 1e2382c8779e1ee06226f9cc9acbf9a63eb5fc44 /arch/sh/kernel/cpu/sh2a | |
parent | a8f67f4b4d4b74cd14d3540ade8657ebee543340 (diff) |
sh: SH-2A FPU support.
Signed-off-by: Kieran Bingham <kbingham@mpc-data.co.uk>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh/kernel/cpu/sh2a')
-rw-r--r-- | arch/sh/kernel/cpu/sh2a/Makefile | 2 | ||||
-rw-r--r-- | arch/sh/kernel/cpu/sh2a/fpu.c | 633 |
2 files changed, 635 insertions, 0 deletions
diff --git a/arch/sh/kernel/cpu/sh2a/Makefile b/arch/sh/kernel/cpu/sh2a/Makefile index 50e4d0ffdd6..b279cdc3a23 100644 --- a/arch/sh/kernel/cpu/sh2a/Makefile +++ b/arch/sh/kernel/cpu/sh2a/Makefile @@ -6,6 +6,8 @@ obj-y := common.o probe.o opcode_helper.o common-y += $(addprefix ../sh2/, ex.o entry.o) +obj-$(CONFIG_SH_FPU) += fpu.o + obj-$(CONFIG_CPU_SUBTYPE_SH7206) += setup-sh7206.o clock-sh7206.o obj-$(CONFIG_CPU_SUBTYPE_SH7203) += setup-sh7203.o clock-sh7203.o obj-$(CONFIG_CPU_SUBTYPE_SH7263) += setup-sh7203.o clock-sh7203.o diff --git a/arch/sh/kernel/cpu/sh2a/fpu.c b/arch/sh/kernel/cpu/sh2a/fpu.c new file mode 100644 index 00000000000..ff99562456f --- /dev/null +++ b/arch/sh/kernel/cpu/sh2a/fpu.c @@ -0,0 +1,633 @@ +/* + * Save/restore floating point context for signal handlers. + * + * Copyright (C) 1999, 2000 Kaz Kojima & Niibe Yutaka + * + * 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. + * + * 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" + "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("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" + "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" + "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" + "lds %2, fpscr\n\t" + : /* no output */ + : "r" (0), "r" (FPSCR_RCHG), "r" (FPSCR_INIT)); + disable_fpu(); +} + +/* + * Emulate arithmetic ops on denormalized number for some FPU insns. + */ + +/* denormalized float * float */ +static int denormal_mulf(int hx, int hy) +{ + unsigned int ix, iy; + unsigned long long m, n; + int exp, w; + + ix = hx & 0x7fffffff; + iy = hy & 0x7fffffff; + if (iy < 0x00800000 || ix == 0) + return ((hx ^ hy) & 0x80000000); + + exp = (iy & 0x7f800000) >> 23; + ix &= 0x007fffff; + iy = (iy & 0x007fffff) | 0x00800000; + m = (unsigned long long)ix * iy; + n = m; + w = -1; + while (n) { n >>= 1; w++; } + + /* FIXME: use guard bits */ + exp += w - 126 - 46; + if (exp > 0) + ix = ((int) (m >> (w - 23)) & 0x007fffff) | (exp << 23); + else if (exp + 22 >= 0) + ix = (int) (m >> (w - 22 - exp)) & 0x007fffff; + else + ix = 0; + + ix |= (hx ^ hy) & 0x80000000; + return ix; +} + +/* denormalized double * double */ +static void mult64(unsigned long long x, unsigned long long y, + unsigned long long *highp, unsigned long long *lowp) +{ + unsigned long long sub0, sub1, sub2, sub3; + unsigned long long high, low; + + sub0 = (x >> 32) * (unsigned long) (y >> 32); + sub1 = (x & 0xffffffffLL) * (unsigned long) (y >> 32); + sub2 = (x >> 32) * (unsigned long) (y & 0xffffffffLL); + sub3 = (x & 0xffffffffLL) * (unsigned long) (y & 0xffffffffLL); + low = sub3; + high = 0LL; + sub3 += (sub1 << 32); + if (low > sub3) + high++; + low = sub3; + sub3 += (sub2 << 32); + if (low > sub3) + high++; + low = sub3; + high += (sub1 >> 32) + (sub2 >> 32); + high += sub0; + *lowp = low; + *highp = high; +} + +static inline long long rshift64(unsigned long long mh, + unsigned long long ml, int n) +{ + if (n >= 64) + return mh >> (n - 64); + return (mh << (64 - n)) | (ml >> n); +} + +static long long denormal_muld(long long hx, long long hy) +{ + unsigned long long ix, iy; + unsigned long long mh, ml, nh, nl; + int exp, w; + + ix = hx & 0x7fffffffffffffffLL; + iy = hy & 0x7fffffffffffffffLL; + if (iy < 0x0010000000000000LL || ix == 0) + return ((hx ^ hy) & 0x8000000000000000LL); + + exp = (iy & 0x7ff0000000000000LL) >> 52; + ix &= 0x000fffffffffffffLL; + iy = (iy & 0x000fffffffffffffLL) | 0x0010000000000000LL; + mult64(ix, iy, &mh, &ml); + nh = mh; + nl = ml; + w = -1; + if (nh) { + while (nh) { nh >>= 1; w++;} + w += 64; + } else + while (nl) { nl >>= 1; w++;} + + /* FIXME: use guard bits */ + exp += w - 1022 - 52 * 2; + if (exp > 0) + ix = (rshift64(mh, ml, w - 52) & 0x000fffffffffffffLL) + | ((long long)exp << 52); + else if (exp + 51 >= 0) + ix = rshift64(mh, ml, w - 51 - exp) & 0x000fffffffffffffLL; + else + ix = 0; + + ix |= (hx ^ hy) & 0x8000000000000000LL; + return ix; +} + +/* ix - iy where iy: denormal and ix, iy >= 0 */ +static int denormal_subf1(unsigned int ix, unsigned int iy) +{ + int frac; + int exp; + + if (ix < 0x00800000) + return ix - iy; + + exp = (ix & 0x7f800000) >> 23; + if (exp - 1 > 31) + return ix; + iy >>= exp - 1; + if (iy == 0) + return ix; + + frac = (ix & 0x007fffff) | 0x00800000; + frac -= iy; + while (frac < 0x00800000) { + if (--exp == 0) + return frac; + frac <<= 1; + } + + return (exp << 23) | (frac & 0x007fffff); +} + +/* ix + iy where iy: denormal and ix, iy >= 0 */ +static int denormal_addf1(unsigned int ix, unsigned int iy) +{ + int frac; + int exp; + + if (ix < 0x00800000) + return ix + iy; + + exp = (ix & 0x7f800000) >> 23; + if (exp - 1 > 31) + return ix; + iy >>= exp - 1; + if (iy == 0) + return ix; + + frac = (ix & 0x007fffff) | 0x00800000; + frac += iy; + if (frac >= 0x01000000) { + frac >>= 1; + ++exp; + } + + return (exp << 23) | (frac & 0x007fffff); +} + +static int denormal_addf(int hx, int hy) +{ + unsigned int ix, iy; + int sign; + + if ((hx ^ hy) & 0x80000000) { + sign = hx & 0x80000000; + ix = hx & 0x7fffffff; + iy = hy & 0x7fffffff; + if (iy < 0x00800000) { + ix = denormal_subf1(ix, iy); + if (ix < 0) { + ix = -ix; + sign ^= 0x80000000; + } + } else { + ix = denormal_subf1(iy, ix); + sign ^= 0x80000000; + } + } else { + sign = hx & 0x80000000; + ix = hx & 0x7fffffff; + iy = hy & 0x7fffffff; + if (iy < 0x00800000) + ix = denormal_addf1(ix, iy); + else + ix = denormal_addf1(iy, ix); + } + + return sign | ix; +} + +/* ix - iy where iy: denormal and ix, iy >= 0 */ +static long long denormal_subd1(unsigned long long ix, unsigned long long iy) +{ + long long frac; + int exp; + + if (ix < 0x0010000000000000LL) + return ix - iy; + + exp = (ix & 0x7ff0000000000000LL) >> 52; + if (exp - 1 > 63) + return ix; + iy >>= exp - 1; + if (iy == 0) + return ix; + + frac = (ix & 0x000fffffffffffffLL) | 0x0010000000000000LL; + frac -= iy; + while (frac < 0x0010000000000000LL) { + if (--exp == 0) + return frac; + frac <<= 1; + } + + return ((long long)exp << 52) | (frac & 0x000fffffffffffffLL); +} + +/* ix + iy where iy: denormal and ix, iy >= 0 */ +static long long denormal_addd1(unsigned long long ix, unsigned long long iy) +{ + long long frac; + long long exp; + + if (ix < 0x0010000000000000LL) + return ix + iy; + + exp = (ix & 0x7ff0000000000000LL) >> 52; + if (exp - 1 > 63) + return ix; + iy >>= exp - 1; + if (iy == 0) + return ix; + + frac = (ix & 0x000fffffffffffffLL) | 0x0010000000000000LL; + frac += iy; + if (frac >= 0x0020000000000000LL) { + frac >>= 1; + ++exp; + } + + return (exp << 52) | (frac & 0x000fffffffffffffLL); +} + +static long long denormal_addd(long long hx, long long hy) +{ + unsigned long long ix, iy; + long long sign; + + if ((hx ^ hy) & 0x8000000000000000LL) { + sign = hx & 0x8000000000000000LL; + ix = hx & 0x7fffffffffffffffLL; + iy = hy & 0x7fffffffffffffffLL; + if (iy < 0x0010000000000000LL) { + ix = denormal_subd1(ix, iy); + if (ix < 0) { + ix = -ix; + sign ^= 0x8000000000000000LL; + } + } else { + ix = denormal_subd1(iy, ix); + sign ^= 0x8000000000000000LL; + } + } else { + sign = hx & 0x8000000000000000LL; + ix = hx & 0x7fffffffffffffffLL; + iy = hy & 0x7fffffffffffffffLL; + if (iy < 0x0010000000000000LL) + ix = denormal_addd1(ix, iy); + else + ix = denormal_addd1(iy, ix); + } + + return sign | ix; +} + +/** + * 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; + } + +#define FPSCR_FPU_ERROR (1 << 17) + + if ((finsn & 0xf1ff) == 0xf0ad) { /* fcnvsd */ + struct task_struct *tsk = current; + + if ((tsk->thread.fpu.hard.fpscr & FPSCR_FPU_ERROR)) { + /* FPU error */ + denormal_to_double (&tsk->thread.fpu.hard, + (finsn >> 8) & 0xf); + } else + return 0; + + regs->pc = nextpc; + return 1; + } else if ((finsn & 0xf00f) == 0xf002) { /* fmul */ + struct task_struct *tsk = current; + int fpscr; + int n, m, prec; + unsigned int hx, hy; + + n = (finsn >> 8) & 0xf; + m = (finsn >> 4) & 0xf; + hx = tsk->thread.fpu.hard.fp_regs[n]; + hy = tsk->thread.fpu.hard.fp_regs[m]; + fpscr = tsk->thread.fpu.hard.fpscr; + prec = fpscr & (1 << 19); + + if ((fpscr & FPSCR_FPU_ERROR) + && (prec && ((hx & 0x7fffffff) < 0x00100000 + || (hy & 0x7fffffff) < 0x00100000))) { + long long llx, lly; + + /* FPU error because of denormal */ + llx = ((long long) hx << 32) + | tsk->thread.fpu.hard.fp_regs[n+1]; + lly = ((long long) hy << 32) + | tsk->thread.fpu.hard.fp_regs[m+1]; + if ((hx & 0x7fffffff) >= 0x00100000) + llx = denormal_muld(lly, llx); + else + llx = denormal_muld(llx, lly); + tsk->thread.fpu.hard.fp_regs[n] = llx >> 32; + tsk->thread.fpu.hard.fp_regs[n+1] = llx & 0xffffffff; + } else if ((fpscr & FPSCR_FPU_ERROR) + && (!prec && ((hx & 0x7fffffff) < 0x00800000 + || (hy & 0x7fffffff) < 0x00800000))) { + /* FPU error because of denormal */ + if ((hx & 0x7fffffff) >= 0x00800000) + hx = denormal_mulf(hy, hx); + else + hx = denormal_mulf(hx, hy); + tsk->thread.fpu.hard.fp_regs[n] = hx; + } else + return 0; + + regs->pc = nextpc; + return 1; + } else if ((finsn & 0xf00e) == 0xf000) { /* fadd, fsub */ + struct task_struct *tsk = current; + int fpscr; + int n, m, prec; + unsigned int hx, hy; + + n = (finsn >> 8) & 0xf; + m = (finsn >> 4) & 0xf; + hx = tsk->thread.fpu.hard.fp_regs[n]; + hy = tsk->thread.fpu.hard.fp_regs[m]; + fpscr = tsk->thread.fpu.hard.fpscr; + prec = fpscr & (1 << 19); + + if ((fpscr & FPSCR_FPU_ERROR) + && (prec && ((hx & 0x7fffffff) < 0x00100000 + || (hy & 0x7fffffff) < 0x00100000))) { + long long llx, lly; + + /* FPU error because of denormal */ + llx = ((long long) hx << 32) + | tsk->thread.fpu.hard.fp_regs[n+1]; + lly = ((long long) hy << 32) + | tsk->thread.fpu.hard.fp_regs[m+1]; + if ((finsn & 0xf00f) == 0xf000) + llx = denormal_addd(llx, lly); + else + llx = denormal_addd(llx, lly ^ (1LL << 63)); + tsk->thread.fpu.hard.fp_regs[n] = llx >> 32; + tsk->thread.fpu.hard.fp_regs[n+1] = llx & 0xffffffff; + } else if ((fpscr & FPSCR_FPU_ERROR) + && (!prec && ((hx & 0x7fffffff) < 0x00800000 + || (hy & 0x7fffffff) < 0x00800000))) { + /* FPU error because of denormal */ + if ((finsn & 0xf00f) == 0xf000) + hx = denormal_addf(hx, hy); + else + hx = denormal_addf(hx, hy ^ 0x80000000); + tsk->thread.fpu.hard.fp_regs[n] = hx; + } else + return 0; + + regs->pc = nextpc; + return 1; + } + + return 0; +} + +BUILD_TRAP_HANDLER(fpu_error) +{ + struct task_struct *tsk = current; + TRAP_HANDLER_DECL; + + save_fpu(tsk, regs); + if (ieee_fpe_handler(regs)) { + tsk->thread.fpu.hard.fpscr &= + ~(FPSCR_CAUSE_MASK | FPSCR_FLAG_MASK); + grab_fpu(regs); + restore_fpu(tsk); + set_tsk_thread_flag(tsk, TIF_USEDFPU); + return; + } + + force_sig(SIGFPE, tsk); +} + +BUILD_TRAP_HANDLER(fpu_state_restore) +{ + struct task_struct *tsk = current; + TRAP_HANDLER_DECL; + + grab_fpu(regs); + if (!user_mode(regs)) { + 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); +} |