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Diffstat (limited to 'arch/sh/kernel/cpu/sh4/fpu.c')
-rw-r--r--arch/sh/kernel/cpu/sh4/fpu.c429
1 files changed, 429 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 000000000..69ab4d3c8
--- /dev/null
+++ b/arch/sh/kernel/cpu/sh4/fpu.c
@@ -0,0 +1,429 @@
+/*
+ * 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
+ * Copyright (C) 2006 ST Microelectronics Ltd. (denorm support)
+ *
+ * FIXME! These routines have not been tested for big endian case.
+ */
+#include <linux/sched.h>
+#include <linux/signal.h>
+#include <linux/io.h>
+#include <cpu/fpu.h>
+#include <asm/processor.h>
+#include <asm/fpu.h>
+#include <asm/traps.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
+extern unsigned long long float64_div(unsigned long long a,
+ unsigned long long b);
+extern unsigned long int float32_div(unsigned long int a, unsigned long int b);
+extern unsigned long long float64_mul(unsigned long long a,
+ unsigned long long b);
+extern unsigned long int float32_mul(unsigned long int a, unsigned long int b);
+extern unsigned long long float64_add(unsigned long long a,
+ unsigned long long b);
+extern unsigned long int float32_add(unsigned long int a, unsigned long int b);
+extern unsigned long long float64_sub(unsigned long long a,
+ unsigned long long b);
+extern unsigned long int float32_sub(unsigned long int a, unsigned long int b);
+extern unsigned long int float64_to_float32(unsigned long long a);
+static unsigned int fpu_exception_flags;
+
+/*
+ * Save FPU registers onto task structure.
+ */
+void save_fpu(struct task_struct *tsk)
+{
+ unsigned long dummy;
+
+ 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.xstate->hardfpu.status)),
+ "r"(FPSCR_RCHG), "r"(FPSCR_INIT)
+ :"memory");
+
+ disable_fpu();
+}
+
+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.xstate), "r" (FPSCR_RCHG)
+ :"memory");
+ 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))
+ regs->pr = regs->pc + 4; /* bsr & jsr */
+
+ 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 + instruction_size(insn);
+ finsn = insn;
+ }
+
+ if ((finsn & 0xf1ff) == 0xf0ad) {
+ /* fcnvsd */
+ struct task_struct *tsk = current;
+
+ if ((tsk->thread.xstate->hardfpu.fpscr & FPSCR_CAUSE_ERROR))
+ /* FPU error */
+ denormal_to_double(&tsk->thread.xstate->hardfpu,
+ (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.xstate->hardfpu.fp_regs[n];
+ hy = tsk->thread.xstate->hardfpu.fp_regs[m];
+ fpscr = tsk->thread.xstate->hardfpu.fpscr;
+ prec = fpscr & FPSCR_DBL_PRECISION;
+
+ if ((fpscr & FPSCR_CAUSE_ERROR)
+ && (prec && ((hx & 0x7fffffff) < 0x00100000
+ || (hy & 0x7fffffff) < 0x00100000))) {
+ long long llx, lly;
+
+ /* FPU error because of denormal (doubles) */
+ llx = ((long long)hx << 32)
+ | tsk->thread.xstate->hardfpu.fp_regs[n + 1];
+ lly = ((long long)hy << 32)
+ | tsk->thread.xstate->hardfpu.fp_regs[m + 1];
+ llx = float64_mul(llx, lly);
+ tsk->thread.xstate->hardfpu.fp_regs[n] = llx >> 32;
+ tsk->thread.xstate->hardfpu.fp_regs[n + 1] = llx & 0xffffffff;
+ } else if ((fpscr & FPSCR_CAUSE_ERROR)
+ && (!prec && ((hx & 0x7fffffff) < 0x00800000
+ || (hy & 0x7fffffff) < 0x00800000))) {
+ /* FPU error because of denormal (floats) */
+ hx = float32_mul(hx, hy);
+ tsk->thread.xstate->hardfpu.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.xstate->hardfpu.fp_regs[n];
+ hy = tsk->thread.xstate->hardfpu.fp_regs[m];
+ fpscr = tsk->thread.xstate->hardfpu.fpscr;
+ prec = fpscr & FPSCR_DBL_PRECISION;
+
+ if ((fpscr & FPSCR_CAUSE_ERROR)
+ && (prec && ((hx & 0x7fffffff) < 0x00100000
+ || (hy & 0x7fffffff) < 0x00100000))) {
+ long long llx, lly;
+
+ /* FPU error because of denormal (doubles) */
+ llx = ((long long)hx << 32)
+ | tsk->thread.xstate->hardfpu.fp_regs[n + 1];
+ lly = ((long long)hy << 32)
+ | tsk->thread.xstate->hardfpu.fp_regs[m + 1];
+ if ((finsn & 0xf00f) == 0xf000)
+ llx = float64_add(llx, lly);
+ else
+ llx = float64_sub(llx, lly);
+ tsk->thread.xstate->hardfpu.fp_regs[n] = llx >> 32;
+ tsk->thread.xstate->hardfpu.fp_regs[n + 1] = llx & 0xffffffff;
+ } else if ((fpscr & FPSCR_CAUSE_ERROR)
+ && (!prec && ((hx & 0x7fffffff) < 0x00800000
+ || (hy & 0x7fffffff) < 0x00800000))) {
+ /* FPU error because of denormal (floats) */
+ if ((finsn & 0xf00f) == 0xf000)
+ hx = float32_add(hx, hy);
+ else
+ hx = float32_sub(hx, hy);
+ tsk->thread.xstate->hardfpu.fp_regs[n] = hx;
+ } else
+ return 0;
+
+ regs->pc = nextpc;
+ return 1;
+ } else if ((finsn & 0xf003) == 0xf003) {
+ /* fdiv */
+ 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.xstate->hardfpu.fp_regs[n];
+ hy = tsk->thread.xstate->hardfpu.fp_regs[m];
+ fpscr = tsk->thread.xstate->hardfpu.fpscr;
+ prec = fpscr & FPSCR_DBL_PRECISION;
+
+ if ((fpscr & FPSCR_CAUSE_ERROR)
+ && (prec && ((hx & 0x7fffffff) < 0x00100000
+ || (hy & 0x7fffffff) < 0x00100000))) {
+ long long llx, lly;
+
+ /* FPU error because of denormal (doubles) */
+ llx = ((long long)hx << 32)
+ | tsk->thread.xstate->hardfpu.fp_regs[n + 1];
+ lly = ((long long)hy << 32)
+ | tsk->thread.xstate->hardfpu.fp_regs[m + 1];
+
+ llx = float64_div(llx, lly);
+
+ tsk->thread.xstate->hardfpu.fp_regs[n] = llx >> 32;
+ tsk->thread.xstate->hardfpu.fp_regs[n + 1] = llx & 0xffffffff;
+ } else if ((fpscr & FPSCR_CAUSE_ERROR)
+ && (!prec && ((hx & 0x7fffffff) < 0x00800000
+ || (hy & 0x7fffffff) < 0x00800000))) {
+ /* FPU error because of denormal (floats) */
+ hx = float32_div(hx, hy);
+ tsk->thread.xstate->hardfpu.fp_regs[n] = hx;
+ } else
+ return 0;
+
+ regs->pc = nextpc;
+ return 1;
+ } else if ((finsn & 0xf0bd) == 0xf0bd) {
+ /* fcnvds - double to single precision convert */
+ struct task_struct *tsk = current;
+ int m;
+ unsigned int hx;
+
+ m = (finsn >> 8) & 0x7;
+ hx = tsk->thread.xstate->hardfpu.fp_regs[m];
+
+ if ((tsk->thread.xstate->hardfpu.fpscr & FPSCR_CAUSE_ERROR)
+ && ((hx & 0x7fffffff) < 0x00100000)) {
+ /* subnormal double to float conversion */
+ long long llx;
+
+ llx = ((long long)tsk->thread.xstate->hardfpu.fp_regs[m] << 32)
+ | tsk->thread.xstate->hardfpu.fp_regs[m + 1];
+
+ tsk->thread.xstate->hardfpu.fpul = float64_to_float32(llx);
+ } else
+ return 0;
+
+ regs->pc = nextpc;
+ return 1;
+ }
+
+ return 0;
+}
+
+void float_raise(unsigned int flags)
+{
+ fpu_exception_flags |= flags;
+}
+
+int float_rounding_mode(void)
+{
+ struct task_struct *tsk = current;
+ int roundingMode = FPSCR_ROUNDING_MODE(tsk->thread.xstate->hardfpu.fpscr);
+ return roundingMode;
+}
+
+BUILD_TRAP_HANDLER(fpu_error)
+{
+ struct task_struct *tsk = current;
+ TRAP_HANDLER_DECL;
+
+ __unlazy_fpu(tsk, regs);
+ fpu_exception_flags = 0;
+ if (ieee_fpe_handler(regs)) {
+ tsk->thread.xstate->hardfpu.fpscr &=
+ ~(FPSCR_CAUSE_MASK | FPSCR_FLAG_MASK);
+ tsk->thread.xstate->hardfpu.fpscr |= fpu_exception_flags;
+ /* Set the FPSCR flag as well as cause bits - simply
+ * replicate the cause */
+ tsk->thread.xstate->hardfpu.fpscr |= (fpu_exception_flags >> 10);
+ grab_fpu(regs);
+ restore_fpu(tsk);
+ task_thread_info(tsk)->status |= TS_USEDFPU;
+ if ((((tsk->thread.xstate->hardfpu.fpscr & FPSCR_ENABLE_MASK) >> 7) &
+ (fpu_exception_flags >> 2)) == 0) {
+ return;
+ }
+ }
+
+ force_sig(SIGFPE, tsk);
+}
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