573 lines
13 KiB
C
573 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Save/restore floating point context for signal handlers.
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*
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* Copyright (C) 1999, 2000 Kaz Kojima & Niibe Yutaka
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*
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* FIXME! These routines can be optimized in big endian case.
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*/
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#include <linux/sched/signal.h>
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#include <linux/signal.h>
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#include <asm/processor.h>
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#include <asm/io.h>
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#include <asm/fpu.h>
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#include <asm/traps.h>
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/* The PR (precision) bit in the FP Status Register must be clear when
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* an frchg instruction is executed, otherwise the instruction is undefined.
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* Executing frchg with PR set causes a trap on some SH4 implementations.
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*/
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#define FPSCR_RCHG 0x00000000
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/*
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* Save FPU registers onto task structure.
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*/
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void save_fpu(struct task_struct *tsk)
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{
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unsigned long dummy;
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enable_fpu();
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asm volatile("sts.l fpul, @-%0\n\t"
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"sts.l fpscr, @-%0\n\t"
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"fmov.s fr15, @-%0\n\t"
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"fmov.s fr14, @-%0\n\t"
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"fmov.s fr13, @-%0\n\t"
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"fmov.s fr12, @-%0\n\t"
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"fmov.s fr11, @-%0\n\t"
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"fmov.s fr10, @-%0\n\t"
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"fmov.s fr9, @-%0\n\t"
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"fmov.s fr8, @-%0\n\t"
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"fmov.s fr7, @-%0\n\t"
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"fmov.s fr6, @-%0\n\t"
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"fmov.s fr5, @-%0\n\t"
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"fmov.s fr4, @-%0\n\t"
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"fmov.s fr3, @-%0\n\t"
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"fmov.s fr2, @-%0\n\t"
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"fmov.s fr1, @-%0\n\t"
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"fmov.s fr0, @-%0\n\t"
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"lds %3, fpscr\n\t"
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: "=r" (dummy)
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: "0" ((char *)(&tsk->thread.xstate->hardfpu.status)),
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"r" (FPSCR_RCHG),
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"r" (FPSCR_INIT)
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: "memory");
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disable_fpu();
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}
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void restore_fpu(struct task_struct *tsk)
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{
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unsigned long dummy;
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enable_fpu();
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asm volatile("fmov.s @%0+, fr0\n\t"
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"fmov.s @%0+, fr1\n\t"
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"fmov.s @%0+, fr2\n\t"
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"fmov.s @%0+, fr3\n\t"
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"fmov.s @%0+, fr4\n\t"
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"fmov.s @%0+, fr5\n\t"
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"fmov.s @%0+, fr6\n\t"
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"fmov.s @%0+, fr7\n\t"
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"fmov.s @%0+, fr8\n\t"
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"fmov.s @%0+, fr9\n\t"
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"fmov.s @%0+, fr10\n\t"
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"fmov.s @%0+, fr11\n\t"
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"fmov.s @%0+, fr12\n\t"
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"fmov.s @%0+, fr13\n\t"
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"fmov.s @%0+, fr14\n\t"
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"fmov.s @%0+, fr15\n\t"
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"lds.l @%0+, fpscr\n\t"
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"lds.l @%0+, fpul\n\t"
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: "=r" (dummy)
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: "0" (tsk->thread.xstate), "r" (FPSCR_RCHG)
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: "memory");
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disable_fpu();
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}
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/*
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* Emulate arithmetic ops on denormalized number for some FPU insns.
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*/
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/* denormalized float * float */
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static int denormal_mulf(int hx, int hy)
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{
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unsigned int ix, iy;
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unsigned long long m, n;
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int exp, w;
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ix = hx & 0x7fffffff;
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iy = hy & 0x7fffffff;
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if (iy < 0x00800000 || ix == 0)
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return ((hx ^ hy) & 0x80000000);
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exp = (iy & 0x7f800000) >> 23;
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ix &= 0x007fffff;
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iy = (iy & 0x007fffff) | 0x00800000;
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m = (unsigned long long)ix * iy;
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n = m;
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w = -1;
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while (n) { n >>= 1; w++; }
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/* FIXME: use guard bits */
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exp += w - 126 - 46;
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if (exp > 0)
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ix = ((int) (m >> (w - 23)) & 0x007fffff) | (exp << 23);
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else if (exp + 22 >= 0)
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ix = (int) (m >> (w - 22 - exp)) & 0x007fffff;
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else
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ix = 0;
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ix |= (hx ^ hy) & 0x80000000;
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return ix;
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}
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/* denormalized double * double */
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static void mult64(unsigned long long x, unsigned long long y,
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unsigned long long *highp, unsigned long long *lowp)
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{
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unsigned long long sub0, sub1, sub2, sub3;
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unsigned long long high, low;
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sub0 = (x >> 32) * (unsigned long) (y >> 32);
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sub1 = (x & 0xffffffffLL) * (unsigned long) (y >> 32);
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sub2 = (x >> 32) * (unsigned long) (y & 0xffffffffLL);
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sub3 = (x & 0xffffffffLL) * (unsigned long) (y & 0xffffffffLL);
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low = sub3;
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high = 0LL;
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sub3 += (sub1 << 32);
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if (low > sub3)
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high++;
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low = sub3;
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sub3 += (sub2 << 32);
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if (low > sub3)
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high++;
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low = sub3;
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high += (sub1 >> 32) + (sub2 >> 32);
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high += sub0;
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*lowp = low;
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*highp = high;
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}
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static inline long long rshift64(unsigned long long mh,
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unsigned long long ml, int n)
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{
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if (n >= 64)
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return mh >> (n - 64);
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return (mh << (64 - n)) | (ml >> n);
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}
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static long long denormal_muld(long long hx, long long hy)
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{
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unsigned long long ix, iy;
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unsigned long long mh, ml, nh, nl;
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int exp, w;
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ix = hx & 0x7fffffffffffffffLL;
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iy = hy & 0x7fffffffffffffffLL;
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if (iy < 0x0010000000000000LL || ix == 0)
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return ((hx ^ hy) & 0x8000000000000000LL);
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exp = (iy & 0x7ff0000000000000LL) >> 52;
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ix &= 0x000fffffffffffffLL;
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iy = (iy & 0x000fffffffffffffLL) | 0x0010000000000000LL;
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mult64(ix, iy, &mh, &ml);
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nh = mh;
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nl = ml;
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w = -1;
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if (nh) {
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while (nh) { nh >>= 1; w++;}
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w += 64;
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} else
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while (nl) { nl >>= 1; w++;}
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/* FIXME: use guard bits */
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exp += w - 1022 - 52 * 2;
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if (exp > 0)
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ix = (rshift64(mh, ml, w - 52) & 0x000fffffffffffffLL)
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| ((long long)exp << 52);
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else if (exp + 51 >= 0)
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ix = rshift64(mh, ml, w - 51 - exp) & 0x000fffffffffffffLL;
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else
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ix = 0;
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ix |= (hx ^ hy) & 0x8000000000000000LL;
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return ix;
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}
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/* ix - iy where iy: denormal and ix, iy >= 0 */
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static int denormal_subf1(unsigned int ix, unsigned int iy)
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{
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int frac;
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int exp;
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if (ix < 0x00800000)
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return ix - iy;
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exp = (ix & 0x7f800000) >> 23;
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if (exp - 1 > 31)
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return ix;
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iy >>= exp - 1;
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if (iy == 0)
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return ix;
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frac = (ix & 0x007fffff) | 0x00800000;
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frac -= iy;
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while (frac < 0x00800000) {
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if (--exp == 0)
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return frac;
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frac <<= 1;
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}
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return (exp << 23) | (frac & 0x007fffff);
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}
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/* ix + iy where iy: denormal and ix, iy >= 0 */
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static int denormal_addf1(unsigned int ix, unsigned int iy)
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{
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int frac;
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int exp;
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if (ix < 0x00800000)
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return ix + iy;
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exp = (ix & 0x7f800000) >> 23;
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if (exp - 1 > 31)
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return ix;
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iy >>= exp - 1;
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if (iy == 0)
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return ix;
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frac = (ix & 0x007fffff) | 0x00800000;
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frac += iy;
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if (frac >= 0x01000000) {
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frac >>= 1;
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++exp;
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}
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return (exp << 23) | (frac & 0x007fffff);
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}
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static int denormal_addf(int hx, int hy)
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{
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unsigned int ix, iy;
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int sign;
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if ((hx ^ hy) & 0x80000000) {
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sign = hx & 0x80000000;
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ix = hx & 0x7fffffff;
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iy = hy & 0x7fffffff;
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if (iy < 0x00800000) {
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ix = denormal_subf1(ix, iy);
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if ((int) ix < 0) {
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ix = -ix;
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sign ^= 0x80000000;
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}
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} else {
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ix = denormal_subf1(iy, ix);
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sign ^= 0x80000000;
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}
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} else {
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sign = hx & 0x80000000;
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ix = hx & 0x7fffffff;
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iy = hy & 0x7fffffff;
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if (iy < 0x00800000)
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ix = denormal_addf1(ix, iy);
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else
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ix = denormal_addf1(iy, ix);
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}
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return sign | ix;
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}
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/* ix - iy where iy: denormal and ix, iy >= 0 */
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static long long denormal_subd1(unsigned long long ix, unsigned long long iy)
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{
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long long frac;
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int exp;
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if (ix < 0x0010000000000000LL)
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return ix - iy;
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exp = (ix & 0x7ff0000000000000LL) >> 52;
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if (exp - 1 > 63)
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return ix;
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iy >>= exp - 1;
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if (iy == 0)
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return ix;
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frac = (ix & 0x000fffffffffffffLL) | 0x0010000000000000LL;
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frac -= iy;
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while (frac < 0x0010000000000000LL) {
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if (--exp == 0)
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return frac;
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frac <<= 1;
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}
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return ((long long)exp << 52) | (frac & 0x000fffffffffffffLL);
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}
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/* ix + iy where iy: denormal and ix, iy >= 0 */
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static long long denormal_addd1(unsigned long long ix, unsigned long long iy)
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{
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long long frac;
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long long exp;
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if (ix < 0x0010000000000000LL)
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return ix + iy;
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exp = (ix & 0x7ff0000000000000LL) >> 52;
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if (exp - 1 > 63)
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return ix;
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iy >>= exp - 1;
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if (iy == 0)
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return ix;
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frac = (ix & 0x000fffffffffffffLL) | 0x0010000000000000LL;
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frac += iy;
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if (frac >= 0x0020000000000000LL) {
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frac >>= 1;
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++exp;
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}
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return (exp << 52) | (frac & 0x000fffffffffffffLL);
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}
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static long long denormal_addd(long long hx, long long hy)
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{
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unsigned long long ix, iy;
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long long sign;
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if ((hx ^ hy) & 0x8000000000000000LL) {
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sign = hx & 0x8000000000000000LL;
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ix = hx & 0x7fffffffffffffffLL;
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iy = hy & 0x7fffffffffffffffLL;
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if (iy < 0x0010000000000000LL) {
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ix = denormal_subd1(ix, iy);
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if ((int) ix < 0) {
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ix = -ix;
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sign ^= 0x8000000000000000LL;
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}
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} else {
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ix = denormal_subd1(iy, ix);
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sign ^= 0x8000000000000000LL;
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}
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} else {
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sign = hx & 0x8000000000000000LL;
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ix = hx & 0x7fffffffffffffffLL;
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iy = hy & 0x7fffffffffffffffLL;
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if (iy < 0x0010000000000000LL)
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ix = denormal_addd1(ix, iy);
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else
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ix = denormal_addd1(iy, ix);
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}
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return sign | ix;
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}
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/**
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* denormal_to_double - Given denormalized float number,
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* store double float
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*
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* @fpu: Pointer to sh_fpu_hard structure
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* @n: Index to FP register
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*/
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static void
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denormal_to_double (struct sh_fpu_hard_struct *fpu, int n)
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{
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unsigned long du, dl;
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unsigned long x = fpu->fpul;
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int exp = 1023 - 126;
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if (x != 0 && (x & 0x7f800000) == 0) {
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du = (x & 0x80000000);
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while ((x & 0x00800000) == 0) {
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x <<= 1;
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exp--;
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}
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x &= 0x007fffff;
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du |= (exp << 20) | (x >> 3);
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dl = x << 29;
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fpu->fp_regs[n] = du;
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fpu->fp_regs[n+1] = dl;
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}
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}
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/**
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* ieee_fpe_handler - Handle denormalized number exception
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*
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* @regs: Pointer to register structure
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*
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* Returns 1 when it's handled (should not cause exception).
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*/
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static int
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ieee_fpe_handler (struct pt_regs *regs)
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{
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unsigned short insn = *(unsigned short *) regs->pc;
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unsigned short finsn;
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unsigned long nextpc;
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int nib[4] = {
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(insn >> 12) & 0xf,
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(insn >> 8) & 0xf,
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(insn >> 4) & 0xf,
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insn & 0xf};
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if (nib[0] == 0xb ||
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(nib[0] == 0x4 && nib[2] == 0x0 && nib[3] == 0xb)) /* bsr & jsr */
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regs->pr = regs->pc + 4;
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if (nib[0] == 0xa || nib[0] == 0xb) { /* bra & bsr */
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nextpc = regs->pc + 4 + ((short) ((insn & 0xfff) << 4) >> 3);
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finsn = *(unsigned short *) (regs->pc + 2);
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} else if (nib[0] == 0x8 && nib[1] == 0xd) { /* bt/s */
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if (regs->sr & 1)
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nextpc = regs->pc + 4 + ((char) (insn & 0xff) << 1);
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else
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nextpc = regs->pc + 4;
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finsn = *(unsigned short *) (regs->pc + 2);
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} else if (nib[0] == 0x8 && nib[1] == 0xf) { /* bf/s */
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if (regs->sr & 1)
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nextpc = regs->pc + 4;
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else
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nextpc = regs->pc + 4 + ((char) (insn & 0xff) << 1);
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finsn = *(unsigned short *) (regs->pc + 2);
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} else if (nib[0] == 0x4 && nib[3] == 0xb &&
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(nib[2] == 0x0 || nib[2] == 0x2)) { /* jmp & jsr */
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nextpc = regs->regs[nib[1]];
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finsn = *(unsigned short *) (regs->pc + 2);
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} else if (nib[0] == 0x0 && nib[3] == 0x3 &&
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(nib[2] == 0x0 || nib[2] == 0x2)) { /* braf & bsrf */
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nextpc = regs->pc + 4 + regs->regs[nib[1]];
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finsn = *(unsigned short *) (regs->pc + 2);
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} else if (insn == 0x000b) { /* rts */
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nextpc = regs->pr;
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finsn = *(unsigned short *) (regs->pc + 2);
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} else {
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nextpc = regs->pc + 2;
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finsn = insn;
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}
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#define FPSCR_FPU_ERROR (1 << 17)
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if ((finsn & 0xf1ff) == 0xf0ad) { /* fcnvsd */
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struct task_struct *tsk = current;
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if ((tsk->thread.xstate->hardfpu.fpscr & FPSCR_FPU_ERROR)) {
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/* FPU error */
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denormal_to_double (&tsk->thread.xstate->hardfpu,
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(finsn >> 8) & 0xf);
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} else
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return 0;
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regs->pc = nextpc;
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return 1;
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} else if ((finsn & 0xf00f) == 0xf002) { /* fmul */
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struct task_struct *tsk = current;
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int fpscr;
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int n, m, prec;
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unsigned int hx, hy;
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n = (finsn >> 8) & 0xf;
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m = (finsn >> 4) & 0xf;
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hx = tsk->thread.xstate->hardfpu.fp_regs[n];
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hy = tsk->thread.xstate->hardfpu.fp_regs[m];
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fpscr = tsk->thread.xstate->hardfpu.fpscr;
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prec = fpscr & (1 << 19);
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if ((fpscr & FPSCR_FPU_ERROR)
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&& (prec && ((hx & 0x7fffffff) < 0x00100000
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|| (hy & 0x7fffffff) < 0x00100000))) {
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long long llx, lly;
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/* FPU error because of denormal */
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llx = ((long long) hx << 32)
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| tsk->thread.xstate->hardfpu.fp_regs[n+1];
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lly = ((long long) hy << 32)
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| tsk->thread.xstate->hardfpu.fp_regs[m+1];
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if ((hx & 0x7fffffff) >= 0x00100000)
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llx = denormal_muld(lly, llx);
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else
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llx = denormal_muld(llx, lly);
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tsk->thread.xstate->hardfpu.fp_regs[n] = llx >> 32;
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tsk->thread.xstate->hardfpu.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.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 & (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.xstate->hardfpu.fp_regs[n+1];
|
|
lly = ((long long) hy << 32)
|
|
| tsk->thread.xstate->hardfpu.fp_regs[m+1];
|
|
if ((finsn & 0xf00f) == 0xf000)
|
|
llx = denormal_addd(llx, lly);
|
|
else
|
|
llx = denormal_addd(llx, lly ^ (1LL << 63));
|
|
tsk->thread.xstate->hardfpu.fp_regs[n] = llx >> 32;
|
|
tsk->thread.xstate->hardfpu.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.xstate->hardfpu.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;
|
|
|
|
__unlazy_fpu(tsk, regs);
|
|
if (ieee_fpe_handler(regs)) {
|
|
tsk->thread.xstate->hardfpu.fpscr &=
|
|
~(FPSCR_CAUSE_MASK | FPSCR_FLAG_MASK);
|
|
grab_fpu(regs);
|
|
restore_fpu(tsk);
|
|
task_thread_info(tsk)->status |= TS_USEDFPU;
|
|
return;
|
|
}
|
|
|
|
force_sig(SIGFPE);
|
|
}
|