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| -rw-r--r-- | arch/arm/vfp/vfpdouble.c | 1206 |
1 files changed, 1206 insertions, 0 deletions
diff --git a/arch/arm/vfp/vfpdouble.c b/arch/arm/vfp/vfpdouble.c new file mode 100644 index 000000000..423f56dd4 --- /dev/null +++ b/arch/arm/vfp/vfpdouble.c @@ -0,0 +1,1206 @@ +/* + * linux/arch/arm/vfp/vfpdouble.c + * + * This code is derived in part from John R. Housers softfloat library, which + * carries the following notice: + * + * =========================================================================== + * This C source file is part of the SoftFloat IEC/IEEE Floating-point + * Arithmetic Package, Release 2. + * + * Written by John R. Hauser. This work was made possible in part by the + * International Computer Science Institute, located at Suite 600, 1947 Center + * Street, Berkeley, California 94704. Funding was partially provided by the + * National Science Foundation under grant MIP-9311980. The original version + * of this code was written as part of a project to build a fixed-point vector + * processor in collaboration with the University of California at Berkeley, + * overseen by Profs. Nelson Morgan and John Wawrzynek. More information + * is available through the web page `http://HTTP.CS.Berkeley.EDU/~jhauser/ + * arithmetic/softfloat.html'. + * + * THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE. Although reasonable effort + * has been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT + * TIMES RESULT IN INCORRECT BEHAVIOR. USE OF THIS SOFTWARE IS RESTRICTED TO + * PERSONS AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY + * AND ALL LOSSES, COSTS, OR OTHER PROBLEMS ARISING FROM ITS USE. + * + * Derivative works are acceptable, even for commercial purposes, so long as + * (1) they include prominent notice that the work is derivative, and (2) they + * include prominent notice akin to these three paragraphs for those parts of + * this code that are retained. + * =========================================================================== + */ +#include <linux/kernel.h> +#include <linux/bitops.h> + +#include <asm/div64.h> +#include <asm/vfp.h> + +#include "vfpinstr.h" +#include "vfp.h" + +static struct vfp_double vfp_double_default_qnan = { + .exponent = 2047, + .sign = 0, + .significand = VFP_DOUBLE_SIGNIFICAND_QNAN, +}; + +static void vfp_double_dump(const char *str, struct vfp_double *d) +{ + pr_debug("VFP: %s: sign=%d exponent=%d significand=%016llx\n", + str, d->sign != 0, d->exponent, d->significand); +} + +static void vfp_double_normalise_denormal(struct vfp_double *vd) +{ + int bits = 31 - fls(vd->significand >> 32); + if (bits == 31) + bits = 63 - fls(vd->significand); + + vfp_double_dump("normalise_denormal: in", vd); + + if (bits) { + vd->exponent -= bits - 1; + vd->significand <<= bits; + } + + vfp_double_dump("normalise_denormal: out", vd); +} + +u32 vfp_double_normaliseround(int dd, struct vfp_double *vd, u32 fpscr, u32 exceptions, const char *func) +{ + u64 significand, incr; + int exponent, shift, underflow; + u32 rmode; + + vfp_double_dump("pack: in", vd); + + /* + * Infinities and NaNs are a special case. + */ + if (vd->exponent == 2047 && (vd->significand == 0 || exceptions)) + goto pack; + + /* + * Special-case zero. + */ + if (vd->significand == 0) { + vd->exponent = 0; + goto pack; + } + + exponent = vd->exponent; + significand = vd->significand; + + shift = 32 - fls(significand >> 32); + if (shift == 32) + shift = 64 - fls(significand); + if (shift) { + exponent -= shift; + significand <<= shift; + } + +#ifdef DEBUG + vd->exponent = exponent; + vd->significand = significand; + vfp_double_dump("pack: normalised", vd); +#endif + + /* + * Tiny number? + */ + underflow = exponent < 0; + if (underflow) { + significand = vfp_shiftright64jamming(significand, -exponent); + exponent = 0; +#ifdef DEBUG + vd->exponent = exponent; + vd->significand = significand; + vfp_double_dump("pack: tiny number", vd); +#endif + if (!(significand & ((1ULL << (VFP_DOUBLE_LOW_BITS + 1)) - 1))) + underflow = 0; + } + + /* + * Select rounding increment. + */ + incr = 0; + rmode = fpscr & FPSCR_RMODE_MASK; + + if (rmode == FPSCR_ROUND_NEAREST) { + incr = 1ULL << VFP_DOUBLE_LOW_BITS; + if ((significand & (1ULL << (VFP_DOUBLE_LOW_BITS + 1))) == 0) + incr -= 1; + } else if (rmode == FPSCR_ROUND_TOZERO) { + incr = 0; + } else if ((rmode == FPSCR_ROUND_PLUSINF) ^ (vd->sign != 0)) + incr = (1ULL << (VFP_DOUBLE_LOW_BITS + 1)) - 1; + + pr_debug("VFP: rounding increment = 0x%08llx\n", incr); + + /* + * Is our rounding going to overflow? + */ + if ((significand + incr) < significand) { + exponent += 1; + significand = (significand >> 1) | (significand & 1); + incr >>= 1; +#ifdef DEBUG + vd->exponent = exponent; + vd->significand = significand; + vfp_double_dump("pack: overflow", vd); +#endif + } + + /* + * If any of the low bits (which will be shifted out of the + * number) are non-zero, the result is inexact. + */ + if (significand & ((1 << (VFP_DOUBLE_LOW_BITS + 1)) - 1)) + exceptions |= FPSCR_IXC; + + /* + * Do our rounding. + */ + significand += incr; + + /* + * Infinity? + */ + if (exponent >= 2046) { + exceptions |= FPSCR_OFC | FPSCR_IXC; + if (incr == 0) { + vd->exponent = 2045; + vd->significand = 0x7fffffffffffffffULL; + } else { + vd->exponent = 2047; /* infinity */ + vd->significand = 0; + } + } else { + if (significand >> (VFP_DOUBLE_LOW_BITS + 1) == 0) + exponent = 0; + if (exponent || significand > 0x8000000000000000ULL) + underflow = 0; + if (underflow) + exceptions |= FPSCR_UFC; + vd->exponent = exponent; + vd->significand = significand >> 1; + } + + pack: + vfp_double_dump("pack: final", vd); + { + s64 d = vfp_double_pack(vd); + pr_debug("VFP: %s: d(d%d)=%016llx exceptions=%08x\n", func, + dd, d, exceptions); + vfp_put_double(d, dd); + } + return exceptions; +} + +/* + * Propagate the NaN, setting exceptions if it is signalling. + * 'n' is always a NaN. 'm' may be a number, NaN or infinity. + */ +static u32 +vfp_propagate_nan(struct vfp_double *vdd, struct vfp_double *vdn, + struct vfp_double *vdm, u32 fpscr) +{ + struct vfp_double *nan; + int tn, tm = 0; + + tn = vfp_double_type(vdn); + + if (vdm) + tm = vfp_double_type(vdm); + + if (fpscr & FPSCR_DEFAULT_NAN) + /* + * Default NaN mode - always returns a quiet NaN + */ + nan = &vfp_double_default_qnan; + else { + /* + * Contemporary mode - select the first signalling + * NAN, or if neither are signalling, the first + * quiet NAN. + */ + if (tn == VFP_SNAN || (tm != VFP_SNAN && tn == VFP_QNAN)) + nan = vdn; + else + nan = vdm; + /* + * Make the NaN quiet. + */ + nan->significand |= VFP_DOUBLE_SIGNIFICAND_QNAN; + } + + *vdd = *nan; + + /* + * If one was a signalling NAN, raise invalid operation. + */ + return tn == VFP_SNAN || tm == VFP_SNAN ? FPSCR_IOC : VFP_NAN_FLAG; +} + +/* + * Extended operations + */ +static u32 vfp_double_fabs(int dd, int unused, int dm, u32 fpscr) +{ + vfp_put_double(vfp_double_packed_abs(vfp_get_double(dm)), dd); + return 0; +} + +static u32 vfp_double_fcpy(int dd, int unused, int dm, u32 fpscr) +{ + vfp_put_double(vfp_get_double(dm), dd); + return 0; +} + +static u32 vfp_double_fneg(int dd, int unused, int dm, u32 fpscr) +{ + vfp_put_double(vfp_double_packed_negate(vfp_get_double(dm)), dd); + return 0; +} + +static u32 vfp_double_fsqrt(int dd, int unused, int dm, u32 fpscr) +{ + struct vfp_double vdm, vdd; + int ret, tm; + + vfp_double_unpack(&vdm, vfp_get_double(dm)); + tm = vfp_double_type(&vdm); + if (tm & (VFP_NAN|VFP_INFINITY)) { + struct vfp_double *vdp = &vdd; + + if (tm & VFP_NAN) + ret = vfp_propagate_nan(vdp, &vdm, NULL, fpscr); + else if (vdm.sign == 0) { + sqrt_copy: + vdp = &vdm; + ret = 0; + } else { + sqrt_invalid: + vdp = &vfp_double_default_qnan; + ret = FPSCR_IOC; + } + vfp_put_double(vfp_double_pack(vdp), dd); + return ret; + } + + /* + * sqrt(+/- 0) == +/- 0 + */ + if (tm & VFP_ZERO) + goto sqrt_copy; + + /* + * Normalise a denormalised number + */ + if (tm & VFP_DENORMAL) + vfp_double_normalise_denormal(&vdm); + + /* + * sqrt(<0) = invalid + */ + if (vdm.sign) + goto sqrt_invalid; + + vfp_double_dump("sqrt", &vdm); + + /* + * Estimate the square root. + */ + vdd.sign = 0; + vdd.exponent = ((vdm.exponent - 1023) >> 1) + 1023; + vdd.significand = (u64)vfp_estimate_sqrt_significand(vdm.exponent, vdm.significand >> 32) << 31; + + vfp_double_dump("sqrt estimate1", &vdd); + + vdm.significand >>= 1 + (vdm.exponent & 1); + vdd.significand += 2 + vfp_estimate_div128to64(vdm.significand, 0, vdd.significand); + + vfp_double_dump("sqrt estimate2", &vdd); + + /* + * And now adjust. + */ + if ((vdd.significand & VFP_DOUBLE_LOW_BITS_MASK) <= 5) { + if (vdd.significand < 2) { + vdd.significand = ~0ULL; + } else { + u64 termh, terml, remh, reml; + vdm.significand <<= 2; + mul64to128(&termh, &terml, vdd.significand, vdd.significand); + sub128(&remh, &reml, vdm.significand, 0, termh, terml); + while ((s64)remh < 0) { + vdd.significand -= 1; + shift64left(&termh, &terml, vdd.significand); + terml |= 1; + add128(&remh, &reml, remh, reml, termh, terml); + } + vdd.significand |= (remh | reml) != 0; + } + } + vdd.significand = vfp_shiftright64jamming(vdd.significand, 1); + + return vfp_double_normaliseround(dd, &vdd, fpscr, 0, "fsqrt"); +} + +/* + * Equal := ZC + * Less than := N + * Greater than := C + * Unordered := CV + */ +static u32 vfp_compare(int dd, int signal_on_qnan, int dm, u32 fpscr) +{ + s64 d, m; + u32 ret = 0; + + m = vfp_get_double(dm); + if (vfp_double_packed_exponent(m) == 2047 && vfp_double_packed_mantissa(m)) { + ret |= FPSCR_C | FPSCR_V; + if (signal_on_qnan || !(vfp_double_packed_mantissa(m) & (1ULL << (VFP_DOUBLE_MANTISSA_BITS - 1)))) + /* + * Signalling NaN, or signalling on quiet NaN + */ + ret |= FPSCR_IOC; + } + + d = vfp_get_double(dd); + if (vfp_double_packed_exponent(d) == 2047 && vfp_double_packed_mantissa(d)) { + ret |= FPSCR_C | FPSCR_V; + if (signal_on_qnan || !(vfp_double_packed_mantissa(d) & (1ULL << (VFP_DOUBLE_MANTISSA_BITS - 1)))) + /* + * Signalling NaN, or signalling on quiet NaN + */ + ret |= FPSCR_IOC; + } + + if (ret == 0) { + if (d == m || vfp_double_packed_abs(d | m) == 0) { + /* + * equal + */ + ret |= FPSCR_Z | FPSCR_C; + } else if (vfp_double_packed_sign(d ^ m)) { + /* + * different signs + */ + if (vfp_double_packed_sign(d)) + /* + * d is negative, so d < m + */ + ret |= FPSCR_N; + else + /* + * d is positive, so d > m + */ + ret |= FPSCR_C; + } else if ((vfp_double_packed_sign(d) != 0) ^ (d < m)) { + /* + * d < m + */ + ret |= FPSCR_N; + } else if ((vfp_double_packed_sign(d) != 0) ^ (d > m)) { + /* + * d > m + */ + ret |= FPSCR_C; + } + } + + return ret; +} + +static u32 vfp_double_fcmp(int dd, int unused, int dm, u32 fpscr) +{ + return vfp_compare(dd, 0, dm, fpscr); +} + +static u32 vfp_double_fcmpe(int dd, int unused, int dm, u32 fpscr) +{ + return vfp_compare(dd, 1, dm, fpscr); +} + +static u32 vfp_double_fcmpz(int dd, int unused, int dm, u32 fpscr) +{ + return vfp_compare(dd, 0, VFP_REG_ZERO, fpscr); +} + +static u32 vfp_double_fcmpez(int dd, int unused, int dm, u32 fpscr) +{ + return vfp_compare(dd, 1, VFP_REG_ZERO, fpscr); +} + +static u32 vfp_double_fcvts(int sd, int unused, int dm, u32 fpscr) +{ + struct vfp_double vdm; + struct vfp_single vsd; + int tm; + u32 exceptions = 0; + + vfp_double_unpack(&vdm, vfp_get_double(dm)); + + tm = vfp_double_type(&vdm); + + /* + * If we have a signalling NaN, signal invalid operation. + */ + if (tm == VFP_SNAN) + exceptions = FPSCR_IOC; + + if (tm & VFP_DENORMAL) + vfp_double_normalise_denormal(&vdm); + + vsd.sign = vdm.sign; + vsd.significand = vfp_hi64to32jamming(vdm.significand); + + /* + * If we have an infinity or a NaN, the exponent must be 255 + */ + if (tm & (VFP_INFINITY|VFP_NAN)) { + vsd.exponent = 255; + if (tm == VFP_QNAN) + vsd.significand |= VFP_SINGLE_SIGNIFICAND_QNAN; + goto pack_nan; + } else if (tm & VFP_ZERO) + vsd.exponent = 0; + else + vsd.exponent = vdm.exponent - (1023 - 127); + + return vfp_single_normaliseround(sd, &vsd, fpscr, exceptions, "fcvts"); + + pack_nan: + vfp_put_float(vfp_single_pack(&vsd), sd); + return exceptions; +} + +static u32 vfp_double_fuito(int dd, int unused, int dm, u32 fpscr) +{ + struct vfp_double vdm; + u32 m = vfp_get_float(dm); + + vdm.sign = 0; + vdm.exponent = 1023 + 63 - 1; + vdm.significand = (u64)m; + + return vfp_double_normaliseround(dd, &vdm, fpscr, 0, "fuito"); +} + +static u32 vfp_double_fsito(int dd, int unused, int dm, u32 fpscr) +{ + struct vfp_double vdm; + u32 m = vfp_get_float(dm); + + vdm.sign = (m & 0x80000000) >> 16; + vdm.exponent = 1023 + 63 - 1; + vdm.significand = vdm.sign ? -m : m; + + return vfp_double_normaliseround(dd, &vdm, fpscr, 0, "fsito"); +} + +static u32 vfp_double_ftoui(int sd, int unused, int dm, u32 fpscr) +{ + struct vfp_double vdm; + u32 d, exceptions = 0; + int rmode = fpscr & FPSCR_RMODE_MASK; + int tm; + + vfp_double_unpack(&vdm, vfp_get_double(dm)); + + /* + * Do we have a denormalised number? + */ + tm = vfp_double_type(&vdm); + if (tm & VFP_DENORMAL) + exceptions |= FPSCR_IDC; + + if (tm & VFP_NAN) + vdm.sign = 0; + + if (vdm.exponent >= 1023 + 32) { + d = vdm.sign ? 0 : 0xffffffff; + exceptions = FPSCR_IOC; + } else if (vdm.exponent >= 1023 - 1) { + int shift = 1023 + 63 - vdm.exponent; + u64 rem, incr = 0; + + /* + * 2^0 <= m < 2^32-2^8 + */ + d = (vdm.significand << 1) >> shift; + rem = vdm.significand << (65 - shift); + + if (rmode == FPSCR_ROUND_NEAREST) { + incr = 0x8000000000000000ULL; + if ((d & 1) == 0) + incr -= 1; + } else if (rmode == FPSCR_ROUND_TOZERO) { + incr = 0; + } else if ((rmode == FPSCR_ROUND_PLUSINF) ^ (vdm.sign != 0)) { + incr = ~0ULL; + } + + if ((rem + incr) < rem) { + if (d < 0xffffffff) + d += 1; + else + exceptions |= FPSCR_IOC; + } + + if (d && vdm.sign) { + d = 0; + exceptions |= FPSCR_IOC; + } else if (rem) + exceptions |= FPSCR_IXC; + } else { + d = 0; + if (vdm.exponent | vdm.significand) { + exceptions |= FPSCR_IXC; + if (rmode == FPSCR_ROUND_PLUSINF && vdm.sign == 0) + d = 1; + else if (rmode == FPSCR_ROUND_MINUSINF && vdm.sign) { + d = 0; + exceptions |= FPSCR_IOC; + } + } + } + + pr_debug("VFP: ftoui: d(s%d)=%08x exceptions=%08x\n", sd, d, exceptions); + + vfp_put_float(d, sd); + + return exceptions; +} + +static u32 vfp_double_ftouiz(int sd, int unused, int dm, u32 fpscr) +{ + return vfp_double_ftoui(sd, unused, dm, FPSCR_ROUND_TOZERO); +} + +static u32 vfp_double_ftosi(int sd, int unused, int dm, u32 fpscr) +{ + struct vfp_double vdm; + u32 d, exceptions = 0; + int rmode = fpscr & FPSCR_RMODE_MASK; + int tm; + + vfp_double_unpack(&vdm, vfp_get_double(dm)); + vfp_double_dump("VDM", &vdm); + + /* + * Do we have denormalised number? + */ + tm = vfp_double_type(&vdm); + if (tm & VFP_DENORMAL) + exceptions |= FPSCR_IDC; + + if (tm & VFP_NAN) { + d = 0; + exceptions |= FPSCR_IOC; + } else if (vdm.exponent >= 1023 + 32) { + d = 0x7fffffff; + if (vdm.sign) + d = ~d; + exceptions |= FPSCR_IOC; + } else if (vdm.exponent >= 1023 - 1) { + int shift = 1023 + 63 - vdm.exponent; /* 58 */ + u64 rem, incr = 0; + + d = (vdm.significand << 1) >> shift; + rem = vdm.significand << (65 - shift); + + if (rmode == FPSCR_ROUND_NEAREST) { + incr = 0x8000000000000000ULL; + if ((d & 1) == 0) + incr -= 1; + } else if (rmode == FPSCR_ROUND_TOZERO) { + incr = 0; + } else if ((rmode == FPSCR_ROUND_PLUSINF) ^ (vdm.sign != 0)) { + incr = ~0ULL; + } + + if ((rem + incr) < rem && d < 0xffffffff) + d += 1; + if (d > 0x7fffffff + (vdm.sign != 0)) { + d = 0x7fffffff + (vdm.sign != 0); + exceptions |= FPSCR_IOC; + } else if (rem) + exceptions |= FPSCR_IXC; + + if (vdm.sign) + d = -d; + } else { + d = 0; + if (vdm.exponent | vdm.significand) { + exceptions |= FPSCR_IXC; + if (rmode == FPSCR_ROUND_PLUSINF && vdm.sign == 0) + d = 1; + else if (rmode == FPSCR_ROUND_MINUSINF && vdm.sign) + d = -1; + } + } + + pr_debug("VFP: ftosi: d(s%d)=%08x exceptions=%08x\n", sd, d, exceptions); + + vfp_put_float((s32)d, sd); + + return exceptions; +} + +static u32 vfp_double_ftosiz(int dd, int unused, int dm, u32 fpscr) +{ + return vfp_double_ftosi(dd, unused, dm, FPSCR_ROUND_TOZERO); +} + + +static struct op fops_ext[32] = { + [FEXT_TO_IDX(FEXT_FCPY)] = { vfp_double_fcpy, 0 }, + [FEXT_TO_IDX(FEXT_FABS)] = { vfp_double_fabs, 0 }, + [FEXT_TO_IDX(FEXT_FNEG)] = { vfp_double_fneg, 0 }, + [FEXT_TO_IDX(FEXT_FSQRT)] = { vfp_double_fsqrt, 0 }, + [FEXT_TO_IDX(FEXT_FCMP)] = { vfp_double_fcmp, OP_SCALAR }, + [FEXT_TO_IDX(FEXT_FCMPE)] = { vfp_double_fcmpe, OP_SCALAR }, + [FEXT_TO_IDX(FEXT_FCMPZ)] = { vfp_double_fcmpz, OP_SCALAR }, + [FEXT_TO_IDX(FEXT_FCMPEZ)] = { vfp_double_fcmpez, OP_SCALAR }, + [FEXT_TO_IDX(FEXT_FCVT)] = { vfp_double_fcvts, OP_SCALAR|OP_SD }, + [FEXT_TO_IDX(FEXT_FUITO)] = { vfp_double_fuito, OP_SCALAR|OP_SM }, + [FEXT_TO_IDX(FEXT_FSITO)] = { vfp_double_fsito, OP_SCALAR|OP_SM }, + [FEXT_TO_IDX(FEXT_FTOUI)] = { vfp_double_ftoui, OP_SCALAR|OP_SD }, + [FEXT_TO_IDX(FEXT_FTOUIZ)] = { vfp_double_ftouiz, OP_SCALAR|OP_SD }, + [FEXT_TO_IDX(FEXT_FTOSI)] = { vfp_double_ftosi, OP_SCALAR|OP_SD }, + [FEXT_TO_IDX(FEXT_FTOSIZ)] = { vfp_double_ftosiz, OP_SCALAR|OP_SD }, +}; + + + + +static u32 +vfp_double_fadd_nonnumber(struct vfp_double *vdd, struct vfp_double *vdn, + struct vfp_double *vdm, u32 fpscr) +{ + struct vfp_double *vdp; + u32 exceptions = 0; + int tn, tm; + + tn = vfp_double_type(vdn); + tm = vfp_double_type(vdm); + + if (tn & tm & VFP_INFINITY) { + /* + * Two infinities. Are they different signs? + */ + if (vdn->sign ^ vdm->sign) { + /* + * different signs -> invalid + */ + exceptions = FPSCR_IOC; + vdp = &vfp_double_default_qnan; + } else { + /* + * same signs -> valid + */ + vdp = vdn; + } + } else if (tn & VFP_INFINITY && tm & VFP_NUMBER) { + /* + * One infinity and one number -> infinity + */ + vdp = vdn; + } else { + /* + * 'n' is a NaN of some type + */ + return vfp_propagate_nan(vdd, vdn, vdm, fpscr); + } + *vdd = *vdp; + return exceptions; +} + +static u32 +vfp_double_add(struct vfp_double *vdd, struct vfp_double *vdn, + struct vfp_double *vdm, u32 fpscr) +{ + u32 exp_diff; + u64 m_sig; + + if (vdn->significand & (1ULL << 63) || + vdm->significand & (1ULL << 63)) { + pr_info("VFP: bad FP values in %s\n", __func__); + vfp_double_dump("VDN", vdn); + vfp_double_dump("VDM", vdm); + } + + /* + * Ensure that 'n' is the largest magnitude number. Note that + * if 'n' and 'm' have equal exponents, we do not swap them. + * This ensures that NaN propagation works correctly. + */ + if (vdn->exponent < vdm->exponent) { + struct vfp_double *t = vdn; + vdn = vdm; + vdm = t; + } + + /* + * Is 'n' an infinity or a NaN? Note that 'm' may be a number, + * infinity or a NaN here. + */ + if (vdn->exponent == 2047) + return vfp_double_fadd_nonnumber(vdd, vdn, vdm, fpscr); + + /* + * We have two proper numbers, where 'vdn' is the larger magnitude. + * + * Copy 'n' to 'd' before doing the arithmetic. + */ + *vdd = *vdn; + + /* + * Align 'm' with the result. + */ + exp_diff = vdn->exponent - vdm->exponent; + m_sig = vfp_shiftright64jamming(vdm->significand, exp_diff); + + /* + * If the signs are different, we are really subtracting. + */ + if (vdn->sign ^ vdm->sign) { + m_sig = vdn->significand - m_sig; + if ((s64)m_sig < 0) { + vdd->sign = vfp_sign_negate(vdd->sign); + m_sig = -m_sig; + } else if (m_sig == 0) { + vdd->sign = (fpscr & FPSCR_RMODE_MASK) == + FPSCR_ROUND_MINUSINF ? 0x8000 : 0; + } + } else { + m_sig += vdn->significand; + } + vdd->significand = m_sig; + + return 0; +} + +static u32 +vfp_double_multiply(struct vfp_double *vdd, struct vfp_double *vdn, + struct vfp_double *vdm, u32 fpscr) +{ + vfp_double_dump("VDN", vdn); + vfp_double_dump("VDM", vdm); + + /* + * Ensure that 'n' is the largest magnitude number. Note that + * if 'n' and 'm' have equal exponents, we do not swap them. + * This ensures that NaN propagation works correctly. + */ + if (vdn->exponent < vdm->exponent) { + struct vfp_double *t = vdn; + vdn = vdm; + vdm = t; + pr_debug("VFP: swapping M <-> N\n"); + } + + vdd->sign = vdn->sign ^ vdm->sign; + + /* + * If 'n' is an infinity or NaN, handle it. 'm' may be anything. + */ + if (vdn->exponent == 2047) { + if (vdn->significand || (vdm->exponent == 2047 && vdm->significand)) + return vfp_propagate_nan(vdd, vdn, vdm, fpscr); + if ((vdm->exponent | vdm->significand) == 0) { + *vdd = vfp_double_default_qnan; + return FPSCR_IOC; + } + vdd->exponent = vdn->exponent; + vdd->significand = 0; + return 0; + } + + /* + * If 'm' is zero, the result is always zero. In this case, + * 'n' may be zero or a number, but it doesn't matter which. + */ + if ((vdm->exponent | vdm->significand) == 0) { + vdd->exponent = 0; + vdd->significand = 0; + return 0; + } + + /* + * We add 2 to the destination exponent for the same reason + * as the addition case - though this time we have +1 from + * each input operand. + */ + vdd->exponent = vdn->exponent + vdm->exponent - 1023 + 2; + vdd->significand = vfp_hi64multiply64(vdn->significand, vdm->significand); + + vfp_double_dump("VDD", vdd); + return 0; +} + +#define NEG_MULTIPLY (1 << 0) +#define NEG_SUBTRACT (1 << 1) + +static u32 +vfp_double_multiply_accumulate(int dd, int dn, int dm, u32 fpscr, u32 negate, char *func) +{ + struct vfp_double vdd, vdp, vdn, vdm; + u32 exceptions; + + vfp_double_unpack(&vdn, vfp_get_double(dn)); + if (vdn.exponent == 0 && vdn.significand) + vfp_double_normalise_denormal(&vdn); + + vfp_double_unpack(&vdm, vfp_get_double(dm)); + if (vdm.exponent == 0 && vdm.significand) + vfp_double_normalise_denormal(&vdm); + + exceptions = vfp_double_multiply(&vdp, &vdn, &vdm, fpscr); + if (negate & NEG_MULTIPLY) + vdp.sign = vfp_sign_negate(vdp.sign); + + vfp_double_unpack(&vdn, vfp_get_double(dd)); + if (vdn.exponent == 0 && vdn.significand) + vfp_double_normalise_denormal(&vdn); + if (negate & NEG_SUBTRACT) + vdn.sign = vfp_sign_negate(vdn.sign); + + exceptions |= vfp_double_add(&vdd, &vdn, &vdp, fpscr); + + return vfp_double_normaliseround(dd, &vdd, fpscr, exceptions, func); +} + +/* + * Standard operations + */ + +/* + * sd = sd + (sn * sm) + */ +static u32 vfp_double_fmac(int dd, int dn, int dm, u32 fpscr) +{ + return vfp_double_multiply_accumulate(dd, dn, dm, fpscr, 0, "fmac"); +} + +/* + * sd = sd - (sn * sm) + */ +static u32 vfp_double_fnmac(int dd, int dn, int dm, u32 fpscr) +{ + return vfp_double_multiply_accumulate(dd, dn, dm, fpscr, NEG_MULTIPLY, "fnmac"); +} + +/* + * sd = -sd + (sn * sm) + */ +static u32 vfp_double_fmsc(int dd, int dn, int dm, u32 fpscr) +{ + return vfp_double_multiply_accumulate(dd, dn, dm, fpscr, NEG_SUBTRACT, "fmsc"); +} + +/* + * sd = -sd - (sn * sm) + */ +static u32 vfp_double_fnmsc(int dd, int dn, int dm, u32 fpscr) +{ + return vfp_double_multiply_accumulate(dd, dn, dm, fpscr, NEG_SUBTRACT | NEG_MULTIPLY, "fnmsc"); +} + +/* + * sd = sn * sm + */ +static u32 vfp_double_fmul(int dd, int dn, int dm, u32 fpscr) +{ + struct vfp_double vdd, vdn, vdm; + u32 exceptions; + + vfp_double_unpack(&vdn, vfp_get_double(dn)); + if (vdn.exponent == 0 && vdn.significand) + vfp_double_normalise_denormal(&vdn); + + vfp_double_unpack(&vdm, vfp_get_double(dm)); + if (vdm.exponent == 0 && vdm.significand) + vfp_double_normalise_denormal(&vdm); + + exceptions = vfp_double_multiply(&vdd, &vdn, &vdm, fpscr); + return vfp_double_normaliseround(dd, &vdd, fpscr, exceptions, "fmul"); +} + +/* + * sd = -(sn * sm) + */ +static u32 vfp_double_fnmul(int dd, int dn, int dm, u32 fpscr) +{ + struct vfp_double vdd, vdn, vdm; + u32 exceptions; + + vfp_double_unpack(&vdn, vfp_get_double(dn)); + if (vdn.exponent == 0 && vdn.significand) + vfp_double_normalise_denormal(&vdn); + + vfp_double_unpack(&vdm, vfp_get_double(dm)); + if (vdm.exponent == 0 && vdm.significand) + vfp_double_normalise_denormal(&vdm); + + exceptions = vfp_double_multiply(&vdd, &vdn, &vdm, fpscr); + vdd.sign = vfp_sign_negate(vdd.sign); + + return vfp_double_normaliseround(dd, &vdd, fpscr, exceptions, "fnmul"); +} + +/* + * sd = sn + sm + */ +static u32 vfp_double_fadd(int dd, int dn, int dm, u32 fpscr) +{ + struct vfp_double vdd, vdn, vdm; + u32 exceptions; + + vfp_double_unpack(&vdn, vfp_get_double(dn)); + if (vdn.exponent == 0 && vdn.significand) + vfp_double_normalise_denormal(&vdn); + + vfp_double_unpack(&vdm, vfp_get_double(dm)); + if (vdm.exponent == 0 && vdm.significand) + vfp_double_normalise_denormal(&vdm); + + exceptions = vfp_double_add(&vdd, &vdn, &vdm, fpscr); + + return vfp_double_normaliseround(dd, &vdd, fpscr, exceptions, "fadd"); +} + +/* + * sd = sn - sm + */ +static u32 vfp_double_fsub(int dd, int dn, int dm, u32 fpscr) +{ + struct vfp_double vdd, vdn, vdm; + u32 exceptions; + + vfp_double_unpack(&vdn, vfp_get_double(dn)); + if (vdn.exponent == 0 && vdn.significand) + vfp_double_normalise_denormal(&vdn); + + vfp_double_unpack(&vdm, vfp_get_double(dm)); + if (vdm.exponent == 0 && vdm.significand) + vfp_double_normalise_denormal(&vdm); + + /* + * Subtraction is like addition, but with a negated operand. + */ + vdm.sign = vfp_sign_negate(vdm.sign); + + exceptions = vfp_double_add(&vdd, &vdn, &vdm, fpscr); + + return vfp_double_normaliseround(dd, &vdd, fpscr, exceptions, "fsub"); +} + +/* + * sd = sn / sm + */ +static u32 vfp_double_fdiv(int dd, int dn, int dm, u32 fpscr) +{ + struct vfp_double vdd, vdn, vdm; + u32 exceptions = 0; + int tm, tn; + + vfp_double_unpack(&vdn, vfp_get_double(dn)); + vfp_double_unpack(&vdm, vfp_get_double(dm)); + + vdd.sign = vdn.sign ^ vdm.sign; + + tn = vfp_double_type(&vdn); + tm = vfp_double_type(&vdm); + + /* + * Is n a NAN? + */ + if (tn & VFP_NAN) + goto vdn_nan; + + /* + * Is m a NAN? + */ + if (tm & VFP_NAN) + goto vdm_nan; + + /* + * If n and m are infinity, the result is invalid + * If n and m are zero, the result is invalid + */ + if (tm & tn & (VFP_INFINITY|VFP_ZERO)) + goto invalid; + + /* + * If n is infinity, the result is infinity + */ + if (tn & VFP_INFINITY) + goto infinity; + + /* + * If m is zero, raise div0 exceptions + */ + if (tm & VFP_ZERO) + goto divzero; + + /* + * If m is infinity, or n is zero, the result is zero + */ + if (tm & VFP_INFINITY || tn & VFP_ZERO) + goto zero; + + if (tn & VFP_DENORMAL) + vfp_double_normalise_denormal(&vdn); + if (tm & VFP_DENORMAL) + vfp_double_normalise_denormal(&vdm); + + /* + * Ok, we have two numbers, we can perform division. + */ + vdd.exponent = vdn.exponent - vdm.exponent + 1023 - 1; + vdm.significand <<= 1; + if (vdm.significand <= (2 * vdn.significand)) { + vdn.significand >>= 1; + vdd.exponent++; + } + vdd.significand = vfp_estimate_div128to64(vdn.significand, 0, vdm.significand); + if ((vdd.significand & 0x1ff) <= 2) { + u64 termh, terml, remh, reml; + mul64to128(&termh, &terml, vdm.significand, vdd.significand); + sub128(&remh, &reml, vdn.significand, 0, termh, terml); + while ((s64)remh < 0) { + vdd.significand -= 1; + add128(&remh, &reml, remh, reml, 0, vdm.significand); + } + vdd.significand |= (reml != 0); + } + return vfp_double_normaliseround(dd, &vdd, fpscr, 0, "fdiv"); + + vdn_nan: + exceptions = vfp_propagate_nan(&vdd, &vdn, &vdm, fpscr); + pack: + vfp_put_double(vfp_double_pack(&vdd), dd); + return exceptions; + + vdm_nan: + exceptions = vfp_propagate_nan(&vdd, &vdm, &vdn, fpscr); + goto pack; + + zero: + vdd.exponent = 0; + vdd.significand = 0; + goto pack; + + divzero: + exceptions = FPSCR_DZC; + infinity: + vdd.exponent = 2047; + vdd.significand = 0; + goto pack; + + invalid: + vfp_put_double(vfp_double_pack(&vfp_double_default_qnan), dd); + return FPSCR_IOC; +} + +static struct op fops[16] = { + [FOP_TO_IDX(FOP_FMAC)] = { vfp_double_fmac, 0 }, + [FOP_TO_IDX(FOP_FNMAC)] = { vfp_double_fnmac, 0 }, + [FOP_TO_IDX(FOP_FMSC)] = { vfp_double_fmsc, 0 }, + [FOP_TO_IDX(FOP_FNMSC)] = { vfp_double_fnmsc, 0 }, + [FOP_TO_IDX(FOP_FMUL)] = { vfp_double_fmul, 0 }, + [FOP_TO_IDX(FOP_FNMUL)] = { vfp_double_fnmul, 0 }, + [FOP_TO_IDX(FOP_FADD)] = { vfp_double_fadd, 0 }, + [FOP_TO_IDX(FOP_FSUB)] = { vfp_double_fsub, 0 }, + [FOP_TO_IDX(FOP_FDIV)] = { vfp_double_fdiv, 0 }, +}; + +#define FREG_BANK(x) ((x) & 0x0c) +#define FREG_IDX(x) ((x) & 3) + +u32 vfp_double_cpdo(u32 inst, u32 fpscr) +{ + u32 op = inst & FOP_MASK; + u32 exceptions = 0; + unsigned int dest; + unsigned int dn = vfp_get_dn(inst); + unsigned int dm; + unsigned int vecitr, veclen, vecstride; + struct op *fop; + + vecstride = (1 + ((fpscr & FPSCR_STRIDE_MASK) == FPSCR_STRIDE_MASK)); + + fop = (op == FOP_EXT) ? &fops_ext[FEXT_TO_IDX(inst)] : &fops[FOP_TO_IDX(op)]; + + /* + * fcvtds takes an sN register number as destination, not dN. + * It also always operates on scalars. + */ + if (fop->flags & OP_SD) + dest = vfp_get_sd(inst); + else + dest = vfp_get_dd(inst); + + /* + * f[us]ito takes a sN operand, not a dN operand. + */ + if (fop->flags & OP_SM) + dm = vfp_get_sm(inst); + else + dm = vfp_get_dm(inst); + + /* + * If destination bank is zero, vector length is always '1'. + * ARM DDI0100F C5.1.3, C5.3.2. + */ + if ((fop->flags & OP_SCALAR) || (FREG_BANK(dest) == 0)) + veclen = 0; + else + veclen = fpscr & FPSCR_LENGTH_MASK; + + pr_debug("VFP: vecstride=%u veclen=%u\n", vecstride, + (veclen >> FPSCR_LENGTH_BIT) + 1); + + if (!fop->fn) + goto invalid; + + for (vecitr = 0; vecitr <= veclen; vecitr += 1 << FPSCR_LENGTH_BIT) { + u32 except; + char type; + + type = fop->flags & OP_SD ? 's' : 'd'; + if (op == FOP_EXT) + pr_debug("VFP: itr%d (%c%u) = op[%u] (d%u)\n", + vecitr >> FPSCR_LENGTH_BIT, + type, dest, dn, dm); + else + pr_debug("VFP: itr%d (%c%u) = (d%u) op[%u] (d%u)\n", + vecitr >> FPSCR_LENGTH_BIT, + type, dest, dn, FOP_TO_IDX(op), dm); + + except = fop->fn(dest, dn, dm, fpscr); + pr_debug("VFP: itr%d: exceptions=%08x\n", + vecitr >> FPSCR_LENGTH_BIT, except); + + exceptions |= except; + + /* + * CHECK: It appears to be undefined whether we stop when + * we encounter an exception. We continue. + */ + dest = FREG_BANK(dest) + ((FREG_IDX(dest) + vecstride) & 3); + dn = FREG_BANK(dn) + ((FREG_IDX(dn) + vecstride) & 3); + if (FREG_BANK(dm) != 0) + dm = FREG_BANK(dm) + ((FREG_IDX(dm) + vecstride) & 3); + } + return exceptions; + + invalid: + return ~0; +} |