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Diffstat (limited to 'arch/arm/vfp/vfpsingle.c')
| -rw-r--r-- | arch/arm/vfp/vfpsingle.c | 1224 |
1 files changed, 1224 insertions, 0 deletions
diff --git a/arch/arm/vfp/vfpsingle.c b/arch/arm/vfp/vfpsingle.c new file mode 100644 index 0000000..6849fe3 --- /dev/null +++ b/arch/arm/vfp/vfpsingle.c @@ -0,0 +1,1224 @@ +/* + * linux/arch/arm/vfp/vfpsingle.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/ptrace.h> +#include <asm/vfp.h> + +#include "vfpinstr.h" +#include "vfp.h" + +static struct vfp_single vfp_single_default_qnan = { + .exponent = 255, + .sign = 0, + .significand = VFP_SINGLE_SIGNIFICAND_QNAN, +}; + +static void vfp_single_dump(const char *str, struct vfp_single *s) +{ + pr_debug("VFP: %s: sign=%d exponent=%d significand=%08x\n", + str, s->sign != 0, s->exponent, s->significand); +} + +static void vfp_single_normalise_denormal(struct vfp_single *vs) +{ + int bits = 31 - fls(vs->significand); + + vfp_single_dump("normalise_denormal: in", vs); + + if (bits) { + vs->exponent -= bits - 1; + vs->significand <<= bits; + } + + vfp_single_dump("normalise_denormal: out", vs); +} + +#ifndef DEBUG +#define vfp_single_normaliseround(sd,vsd,fpscr,except,func) __vfp_single_normaliseround(sd,vsd,fpscr,except) +u32 __vfp_single_normaliseround(int sd, struct vfp_single *vs, u32 fpscr, u32 exceptions) +#else +u32 vfp_single_normaliseround(int sd, struct vfp_single *vs, u32 fpscr, u32 exceptions, const char *func) +#endif +{ + u32 significand, incr, rmode; + int exponent, shift, underflow; + + vfp_single_dump("pack: in", vs); + + /* + * Infinities and NaNs are a special case. + */ + if (vs->exponent == 255 && (vs->significand == 0 || exceptions)) + goto pack; + + /* + * Special-case zero. + */ + if (vs->significand == 0) { + vs->exponent = 0; + goto pack; + } + + exponent = vs->exponent; + significand = vs->significand; + + /* + * Normalise first. Note that we shift the significand up to + * bit 31, so we have VFP_SINGLE_LOW_BITS + 1 below the least + * significant bit. + */ + shift = 32 - fls(significand); + if (shift < 32 && shift) { + exponent -= shift; + significand <<= shift; + } + +#ifdef DEBUG + vs->exponent = exponent; + vs->significand = significand; + vfp_single_dump("pack: normalised", vs); +#endif + + /* + * Tiny number? + */ + underflow = exponent < 0; + if (underflow) { + significand = vfp_shiftright32jamming(significand, -exponent); + exponent = 0; +#ifdef DEBUG + vs->exponent = exponent; + vs->significand = significand; + vfp_single_dump("pack: tiny number", vs); +#endif + if (!(significand & ((1 << (VFP_SINGLE_LOW_BITS + 1)) - 1))) + underflow = 0; + } + + /* + * Select rounding increment. + */ + incr = 0; + rmode = fpscr & FPSCR_RMODE_MASK; + + if (rmode == FPSCR_ROUND_NEAREST) { + incr = 1 << VFP_SINGLE_LOW_BITS; + if ((significand & (1 << (VFP_SINGLE_LOW_BITS + 1))) == 0) + incr -= 1; + } else if (rmode == FPSCR_ROUND_TOZERO) { + incr = 0; + } else if ((rmode == FPSCR_ROUND_PLUSINF) ^ (vs->sign != 0)) + incr = (1 << (VFP_SINGLE_LOW_BITS + 1)) - 1; + + pr_debug("VFP: rounding increment = 0x%08x\n", incr); + + /* + * Is our rounding going to overflow? + */ + if ((significand + incr) < significand) { + exponent += 1; + significand = (significand >> 1) | (significand & 1); + incr >>= 1; +#ifdef DEBUG + vs->exponent = exponent; + vs->significand = significand; + vfp_single_dump("pack: overflow", vs); +#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_SINGLE_LOW_BITS + 1)) - 1)) + exceptions |= FPSCR_IXC; + + /* + * Do our rounding. + */ + significand += incr; + + /* + * Infinity? + */ + if (exponent >= 254) { + exceptions |= FPSCR_OFC | FPSCR_IXC; + if (incr == 0) { + vs->exponent = 253; + vs->significand = 0x7fffffff; + } else { + vs->exponent = 255; /* infinity */ + vs->significand = 0; + } + } else { + if (significand >> (VFP_SINGLE_LOW_BITS + 1) == 0) + exponent = 0; + if (exponent || significand > 0x80000000) + underflow = 0; + if (underflow) + exceptions |= FPSCR_UFC; + vs->exponent = exponent; + vs->significand = significand >> 1; + } + + pack: + vfp_single_dump("pack: final", vs); + { + s32 d = vfp_single_pack(vs); + pr_debug("VFP: %s: d(s%d)=%08x exceptions=%08x\n", func, + sd, d, exceptions); + vfp_put_float(sd, d); + } + + return exceptions & ~VFP_NAN_FLAG; +} + +/* + * 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_single *vsd, struct vfp_single *vsn, + struct vfp_single *vsm, u32 fpscr) +{ + struct vfp_single *nan; + int tn, tm = 0; + + tn = vfp_single_type(vsn); + + if (vsm) + tm = vfp_single_type(vsm); + + if (fpscr & FPSCR_DEFAULT_NAN) + /* + * Default NaN mode - always returns a quiet NaN + */ + nan = &vfp_single_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 = vsn; + else + nan = vsm; + /* + * Make the NaN quiet. + */ + nan->significand |= VFP_SINGLE_SIGNIFICAND_QNAN; + } + + *vsd = *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_single_fabs(int sd, int unused, s32 m, u32 fpscr) +{ + vfp_put_float(sd, vfp_single_packed_abs(m)); + return 0; +} + +static u32 vfp_single_fcpy(int sd, int unused, s32 m, u32 fpscr) +{ + vfp_put_float(sd, m); + return 0; +} + +static u32 vfp_single_fneg(int sd, int unused, s32 m, u32 fpscr) +{ + vfp_put_float(sd, vfp_single_packed_negate(m)); + return 0; +} + +static const u16 sqrt_oddadjust[] = { + 0x0004, 0x0022, 0x005d, 0x00b1, 0x011d, 0x019f, 0x0236, 0x02e0, + 0x039c, 0x0468, 0x0545, 0x0631, 0x072b, 0x0832, 0x0946, 0x0a67 +}; + +static const u16 sqrt_evenadjust[] = { + 0x0a2d, 0x08af, 0x075a, 0x0629, 0x051a, 0x0429, 0x0356, 0x029e, + 0x0200, 0x0179, 0x0109, 0x00af, 0x0068, 0x0034, 0x0012, 0x0002 +}; + +u32 vfp_estimate_sqrt_significand(u32 exponent, u32 significand) +{ + int index; + u32 z, a; + + if ((significand & 0xc0000000) != 0x40000000) { + printk(KERN_WARNING "VFP: estimate_sqrt: invalid significand\n"); + } + + a = significand << 1; + index = (a >> 27) & 15; + if (exponent & 1) { + z = 0x4000 + (a >> 17) - sqrt_oddadjust[index]; + z = ((a / z) << 14) + (z << 15); + a >>= 1; + } else { + z = 0x8000 + (a >> 17) - sqrt_evenadjust[index]; + z = a / z + z; + z = (z >= 0x20000) ? 0xffff8000 : (z << 15); + if (z <= a) + return (s32)a >> 1; + } + return (u32)(((u64)a << 31) / z) + (z >> 1); +} + +static u32 vfp_single_fsqrt(int sd, int unused, s32 m, u32 fpscr) +{ + struct vfp_single vsm, vsd; + int ret, tm; + + vfp_single_unpack(&vsm, m); + tm = vfp_single_type(&vsm); + if (tm & (VFP_NAN|VFP_INFINITY)) { + struct vfp_single *vsp = &vsd; + + if (tm & VFP_NAN) + ret = vfp_propagate_nan(vsp, &vsm, NULL, fpscr); + else if (vsm.sign == 0) { + sqrt_copy: + vsp = &vsm; + ret = 0; + } else { + sqrt_invalid: + vsp = &vfp_single_default_qnan; + ret = FPSCR_IOC; + } + vfp_put_float(sd, vfp_single_pack(vsp)); + return ret; + } + + /* + * sqrt(+/- 0) == +/- 0 + */ + if (tm & VFP_ZERO) + goto sqrt_copy; + + /* + * Normalise a denormalised number + */ + if (tm & VFP_DENORMAL) + vfp_single_normalise_denormal(&vsm); + + /* + * sqrt(<0) = invalid + */ + if (vsm.sign) + goto sqrt_invalid; + + vfp_single_dump("sqrt", &vsm); + + /* + * Estimate the square root. + */ + vsd.sign = 0; + vsd.exponent = ((vsm.exponent - 127) >> 1) + 127; + vsd.significand = vfp_estimate_sqrt_significand(vsm.exponent, vsm.significand) + 2; + + vfp_single_dump("sqrt estimate", &vsd); + + /* + * And now adjust. + */ + if ((vsd.significand & VFP_SINGLE_LOW_BITS_MASK) <= 5) { + if (vsd.significand < 2) { + vsd.significand = 0xffffffff; + } else { + u64 term; + s64 rem; + vsm.significand <<= !(vsm.exponent & 1); + term = (u64)vsd.significand * vsd.significand; + rem = ((u64)vsm.significand << 32) - term; + + pr_debug("VFP: term=%016llx rem=%016llx\n", term, rem); + + while (rem < 0) { + vsd.significand -= 1; + rem += ((u64)vsd.significand << 1) | 1; + } + vsd.significand |= rem != 0; + } + } + vsd.significand = vfp_shiftright32jamming(vsd.significand, 1); + + return vfp_single_normaliseround(sd, &vsd, fpscr, 0, "fsqrt"); +} + +/* + * Equal := ZC + * Less than := N + * Greater than := C + * Unordered := CV + */ +static u32 vfp_compare(int sd, int signal_on_qnan, s32 m, u32 fpscr) +{ + s32 d; + u32 ret = 0; + + d = vfp_get_float(sd); + if (vfp_single_packed_exponent(m) == 255 && vfp_single_packed_mantissa(m)) { + ret |= FPSCR_C | FPSCR_V; + if (signal_on_qnan || !(vfp_single_packed_mantissa(m) & (1 << (VFP_SINGLE_MANTISSA_BITS - 1)))) + /* + * Signalling NaN, or signalling on quiet NaN + */ + ret |= FPSCR_IOC; + } + + if (vfp_single_packed_exponent(d) == 255 && vfp_single_packed_mantissa(d)) { + ret |= FPSCR_C | FPSCR_V; + if (signal_on_qnan || !(vfp_single_packed_mantissa(d) & (1 << (VFP_SINGLE_MANTISSA_BITS - 1)))) + /* + * Signalling NaN, or signalling on quiet NaN + */ + ret |= FPSCR_IOC; + } + + if (ret == 0) { + if (d == m || vfp_single_packed_abs(d | m) == 0) { + /* + * equal + */ + ret |= FPSCR_Z | FPSCR_C; + } else if (vfp_single_packed_sign(d ^ m)) { + /* + * different signs + */ + if (vfp_single_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_single_packed_sign(d) != 0) ^ (d < m)) { + /* + * d < m + */ + ret |= FPSCR_N; + } else if ((vfp_single_packed_sign(d) != 0) ^ (d > m)) { + /* + * d > m + */ + ret |= FPSCR_C; + } + } + return ret; +} + +static u32 vfp_single_fcmp(int sd, int unused, s32 m, u32 fpscr) +{ + return vfp_compare(sd, 0, m, fpscr); +} + +static u32 vfp_single_fcmpe(int sd, int unused, s32 m, u32 fpscr) +{ + return vfp_compare(sd, 1, m, fpscr); +} + +static u32 vfp_single_fcmpz(int sd, int unused, s32 m, u32 fpscr) +{ + return vfp_compare(sd, 0, 0, fpscr); +} + +static u32 vfp_single_fcmpez(int sd, int unused, s32 m, u32 fpscr) +{ + return vfp_compare(sd, 1, 0, fpscr); +} + +static u32 vfp_single_fcvtd(int dd, int unused, s32 m, u32 fpscr) +{ + struct vfp_single vsm; + struct vfp_double vdd; + int tm; + u32 exceptions = 0; + + vfp_single_unpack(&vsm, m); + + tm = vfp_single_type(&vsm); + + /* + * If we have a signalling NaN, signal invalid operation. + */ + if (tm == VFP_SNAN) + exceptions = FPSCR_IOC; + + if (tm & VFP_DENORMAL) + vfp_single_normalise_denormal(&vsm); + + vdd.sign = vsm.sign; + vdd.significand = (u64)vsm.significand << 32; + + /* + * If we have an infinity or NaN, the exponent must be 2047. + */ + if (tm & (VFP_INFINITY|VFP_NAN)) { + vdd.exponent = 2047; + if (tm & VFP_NAN) + vdd.significand |= VFP_DOUBLE_SIGNIFICAND_QNAN; + goto pack_nan; + } else if (tm & VFP_ZERO) + vdd.exponent = 0; + else + vdd.exponent = vsm.exponent + (1023 - 127); + + /* + * Technically, if bit 0 of dd is set, this is an invalid + * instruction. However, we ignore this for efficiency. + */ + return vfp_double_normaliseround(dd, &vdd, fpscr, exceptions, "fcvtd"); + + pack_nan: + vfp_put_double(dd, vfp_double_pack(&vdd)); + return exceptions; +} + +static u32 vfp_single_fuito(int sd, int unused, s32 m, u32 fpscr) +{ + struct vfp_single vs; + + vs.sign = 0; + vs.exponent = 127 + 31 - 1; + vs.significand = (u32)m; + + return vfp_single_normaliseround(sd, &vs, fpscr, 0, "fuito"); +} + +static u32 vfp_single_fsito(int sd, int unused, s32 m, u32 fpscr) +{ + struct vfp_single vs; + + vs.sign = (m & 0x80000000) >> 16; + vs.exponent = 127 + 31 - 1; + vs.significand = vs.sign ? -m : m; + + return vfp_single_normaliseround(sd, &vs, fpscr, 0, "fsito"); +} + +static u32 vfp_single_ftoui(int sd, int unused, s32 m, u32 fpscr) +{ + struct vfp_single vsm; + u32 d, exceptions = 0; + int rmode = fpscr & FPSCR_RMODE_MASK; + int tm; + + vfp_single_unpack(&vsm, m); + vfp_single_dump("VSM", &vsm); + + /* + * Do we have a denormalised number? + */ + tm = vfp_single_type(&vsm); + if (tm & VFP_DENORMAL) + exceptions |= FPSCR_IDC; + + if (tm & VFP_NAN) + vsm.sign = 0; + + if (vsm.exponent >= 127 + 32) { + d = vsm.sign ? 0 : 0xffffffff; + exceptions = FPSCR_IOC; + } else if (vsm.exponent >= 127 - 1) { + int shift = 127 + 31 - vsm.exponent; + u32 rem, incr = 0; + + /* + * 2^0 <= m < 2^32-2^8 + */ + d = (vsm.significand << 1) >> shift; + rem = vsm.significand << (33 - shift); + + if (rmode == FPSCR_ROUND_NEAREST) { + incr = 0x80000000; + if ((d & 1) == 0) + incr -= 1; + } else if (rmode == FPSCR_ROUND_TOZERO) { + incr = 0; + } else if ((rmode == FPSCR_ROUND_PLUSINF) ^ (vsm.sign != 0)) { + incr = ~0; + } + + if ((rem + incr) < rem) { + if (d < 0xffffffff) + d += 1; + else + exceptions |= FPSCR_IOC; + } + + if (d && vsm.sign) { + d = 0; + exceptions |= FPSCR_IOC; + } else if (rem) + exceptions |= FPSCR_IXC; + } else { + d = 0; + if (vsm.exponent | vsm.significand) { + exceptions |= FPSCR_IXC; + if (rmode == FPSCR_ROUND_PLUSINF && vsm.sign == 0) + d = 1; + else if (rmode == FPSCR_ROUND_MINUSINF && vsm.sign) { + d = 0; + exceptions |= FPSCR_IOC; + } + } + } + + pr_debug("VFP: ftoui: d(s%d)=%08x exceptions=%08x\n", sd, d, exceptions); + + vfp_put_float(sd, d); + + return exceptions; +} + +static u32 vfp_single_ftouiz(int sd, int unused, s32 m, u32 fpscr) +{ + return vfp_single_ftoui(sd, unused, m, FPSCR_ROUND_TOZERO); +} + +static u32 vfp_single_ftosi(int sd, int unused, s32 m, u32 fpscr) +{ + struct vfp_single vsm; + u32 d, exceptions = 0; + int rmode = fpscr & FPSCR_RMODE_MASK; + + vfp_single_unpack(&vsm, m); + vfp_single_dump("VSM", &vsm); + + /* + * Do we have a denormalised number? + */ + if (vfp_single_type(&vsm) & VFP_DENORMAL) + exceptions |= FPSCR_IDC; + + if (vsm.exponent >= 127 + 32) { + /* + * m >= 2^31-2^7: invalid + */ + d = 0x7fffffff; + if (vsm.sign) + d = ~d; + exceptions |= FPSCR_IOC; + } else if (vsm.exponent >= 127 - 1) { + int shift = 127 + 31 - vsm.exponent; + u32 rem, incr = 0; + + /* 2^0 <= m <= 2^31-2^7 */ + d = (vsm.significand << 1) >> shift; + rem = vsm.significand << (33 - shift); + + if (rmode == FPSCR_ROUND_NEAREST) { + incr = 0x80000000; + if ((d & 1) == 0) + incr -= 1; + } else if (rmode == FPSCR_ROUND_TOZERO) { + incr = 0; + } else if ((rmode == FPSCR_ROUND_PLUSINF) ^ (vsm.sign != 0)) { + incr = ~0; + } + + if ((rem + incr) < rem && d < 0xffffffff) + d += 1; + if (d > 0x7fffffff + (vsm.sign != 0)) { + d = 0x7fffffff + (vsm.sign != 0); + exceptions |= FPSCR_IOC; + } else if (rem) + exceptions |= FPSCR_IXC; + + if (vsm.sign) + d = -d; + } else { + d = 0; + if (vsm.exponent | vsm.significand) { + exceptions |= FPSCR_IXC; + if (rmode == FPSCR_ROUND_PLUSINF && vsm.sign == 0) + d = 1; + else if (rmode == FPSCR_ROUND_MINUSINF && vsm.sign) + d = -1; + } + } + + pr_debug("VFP: ftosi: d(s%d)=%08x exceptions=%08x\n", sd, d, exceptions); + + vfp_put_float(sd, (s32)d); + + return exceptions; +} + +static u32 vfp_single_ftosiz(int sd, int unused, s32 m, u32 fpscr) +{ + return vfp_single_ftosi(sd, unused, m, FPSCR_ROUND_TOZERO); +} + +static u32 (* const fop_extfns[32])(int sd, int unused, s32 m, u32 fpscr) = { + [FEXT_TO_IDX(FEXT_FCPY)] = vfp_single_fcpy, + [FEXT_TO_IDX(FEXT_FABS)] = vfp_single_fabs, + [FEXT_TO_IDX(FEXT_FNEG)] = vfp_single_fneg, + [FEXT_TO_IDX(FEXT_FSQRT)] = vfp_single_fsqrt, + [FEXT_TO_IDX(FEXT_FCMP)] = vfp_single_fcmp, + [FEXT_TO_IDX(FEXT_FCMPE)] = vfp_single_fcmpe, + [FEXT_TO_IDX(FEXT_FCMPZ)] = vfp_single_fcmpz, + [FEXT_TO_IDX(FEXT_FCMPEZ)] = vfp_single_fcmpez, + [FEXT_TO_IDX(FEXT_FCVT)] = vfp_single_fcvtd, + [FEXT_TO_IDX(FEXT_FUITO)] = vfp_single_fuito, + [FEXT_TO_IDX(FEXT_FSITO)] = vfp_single_fsito, + [FEXT_TO_IDX(FEXT_FTOUI)] = vfp_single_ftoui, + [FEXT_TO_IDX(FEXT_FTOUIZ)] = vfp_single_ftouiz, + [FEXT_TO_IDX(FEXT_FTOSI)] = vfp_single_ftosi, + [FEXT_TO_IDX(FEXT_FTOSIZ)] = vfp_single_ftosiz, +}; + + + + + +static u32 +vfp_single_fadd_nonnumber(struct vfp_single *vsd, struct vfp_single *vsn, + struct vfp_single *vsm, u32 fpscr) +{ + struct vfp_single *vsp; + u32 exceptions = 0; + int tn, tm; + + tn = vfp_single_type(vsn); + tm = vfp_single_type(vsm); + + if (tn & tm & VFP_INFINITY) { + /* + * Two infinities. Are they different signs? + */ + if (vsn->sign ^ vsm->sign) { + /* + * different signs -> invalid + */ + exceptions = FPSCR_IOC; + vsp = &vfp_single_default_qnan; + } else { + /* + * same signs -> valid + */ + vsp = vsn; + } + } else if (tn & VFP_INFINITY && tm & VFP_NUMBER) { + /* + * One infinity and one number -> infinity + */ + vsp = vsn; + } else { + /* + * 'n' is a NaN of some type + */ + return vfp_propagate_nan(vsd, vsn, vsm, fpscr); + } + *vsd = *vsp; + return exceptions; +} + +static u32 +vfp_single_add(struct vfp_single *vsd, struct vfp_single *vsn, + struct vfp_single *vsm, u32 fpscr) +{ + u32 exp_diff, m_sig; + + if (vsn->significand & 0x80000000 || + vsm->significand & 0x80000000) { + pr_info("VFP: bad FP values in %s\n", __func__); + vfp_single_dump("VSN", vsn); + vfp_single_dump("VSM", vsm); + } + + /* + * 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 (vsn->exponent < vsm->exponent) { + struct vfp_single *t = vsn; + vsn = vsm; + vsm = t; + } + + /* + * Is 'n' an infinity or a NaN? Note that 'm' may be a number, + * infinity or a NaN here. + */ + if (vsn->exponent == 255) + return vfp_single_fadd_nonnumber(vsd, vsn, vsm, fpscr); + + /* + * We have two proper numbers, where 'vsn' is the larger magnitude. + * + * Copy 'n' to 'd' before doing the arithmetic. + */ + *vsd = *vsn; + + /* + * Align both numbers. + */ + exp_diff = vsn->exponent - vsm->exponent; + m_sig = vfp_shiftright32jamming(vsm->significand, exp_diff); + + /* + * If the signs are different, we are really subtracting. + */ + if (vsn->sign ^ vsm->sign) { + m_sig = vsn->significand - m_sig; + if ((s32)m_sig < 0) { + vsd->sign = vfp_sign_negate(vsd->sign); + m_sig = -m_sig; + } else if (m_sig == 0) { + vsd->sign = (fpscr & FPSCR_RMODE_MASK) == + FPSCR_ROUND_MINUSINF ? 0x8000 : 0; + } + } else { + m_sig = vsn->significand + m_sig; + } + vsd->significand = m_sig; + + return 0; +} + +static u32 +vfp_single_multiply(struct vfp_single *vsd, struct vfp_single *vsn, struct vfp_single *vsm, u32 fpscr) +{ + vfp_single_dump("VSN", vsn); + vfp_single_dump("VSM", vsm); + + /* + * 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 (vsn->exponent < vsm->exponent) { + struct vfp_single *t = vsn; + vsn = vsm; + vsm = t; + pr_debug("VFP: swapping M <-> N\n"); + } + + vsd->sign = vsn->sign ^ vsm->sign; + + /* + * If 'n' is an infinity or NaN, handle it. 'm' may be anything. + */ + if (vsn->exponent == 255) { + if (vsn->significand || (vsm->exponent == 255 && vsm->significand)) + return vfp_propagate_nan(vsd, vsn, vsm, fpscr); + if ((vsm->exponent | vsm->significand) == 0) { + *vsd = vfp_single_default_qnan; + return FPSCR_IOC; + } + vsd->exponent = vsn->exponent; + vsd->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 ((vsm->exponent | vsm->significand) == 0) { + vsd->exponent = 0; + vsd->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. + */ + vsd->exponent = vsn->exponent + vsm->exponent - 127 + 2; + vsd->significand = vfp_hi64to32jamming((u64)vsn->significand * vsm->significand); + + vfp_single_dump("VSD", vsd); + return 0; +} + +#define NEG_MULTIPLY (1 << 0) +#define NEG_SUBTRACT (1 << 1) + +static u32 +vfp_single_multiply_accumulate(int sd, int sn, s32 m, u32 fpscr, u32 negate, char *func) +{ + struct vfp_single vsd, vsp, vsn, vsm; + u32 exceptions; + s32 v; + + v = vfp_get_float(sn); + pr_debug("VFP: s%u = %08x\n", sn, v); + vfp_single_unpack(&vsn, v); + if (vsn.exponent == 0 && vsn.significand) + vfp_single_normalise_denormal(&vsn); + + vfp_single_unpack(&vsm, m); + if (vsm.exponent == 0 && vsm.significand) + vfp_single_normalise_denormal(&vsm); + + exceptions = vfp_single_multiply(&vsp, &vsn, &vsm, fpscr); + if (negate & NEG_MULTIPLY) + vsp.sign = vfp_sign_negate(vsp.sign); + + v = vfp_get_float(sd); + pr_debug("VFP: s%u = %08x\n", sd, v); + vfp_single_unpack(&vsn, v); + if (negate & NEG_SUBTRACT) + vsn.sign = vfp_sign_negate(vsn.sign); + + exceptions |= vfp_single_add(&vsd, &vsn, &vsp, fpscr); + + return vfp_single_normaliseround(sd, &vsd, fpscr, exceptions, func); +} + +/* + * Standard operations + */ + +/* + * sd = sd + (sn * sm) + */ +static u32 vfp_single_fmac(int sd, int sn, s32 m, u32 fpscr) +{ + return vfp_single_multiply_accumulate(sd, sn, m, fpscr, 0, "fmac"); +} + +/* + * sd = sd - (sn * sm) + */ +static u32 vfp_single_fnmac(int sd, int sn, s32 m, u32 fpscr) +{ + return vfp_single_multiply_accumulate(sd, sn, m, fpscr, NEG_MULTIPLY, "fnmac"); +} + +/* + * sd = -sd + (sn * sm) + */ +static u32 vfp_single_fmsc(int sd, int sn, s32 m, u32 fpscr) +{ + return vfp_single_multiply_accumulate(sd, sn, m, fpscr, NEG_SUBTRACT, "fmsc"); +} + +/* + * sd = -sd - (sn * sm) + */ +static u32 vfp_single_fnmsc(int sd, int sn, s32 m, u32 fpscr) +{ + return vfp_single_multiply_accumulate(sd, sn, m, fpscr, NEG_SUBTRACT | NEG_MULTIPLY, "fnmsc"); +} + +/* + * sd = sn * sm + */ +static u32 vfp_single_fmul(int sd, int sn, s32 m, u32 fpscr) +{ + struct vfp_single vsd, vsn, vsm; + u32 exceptions; + s32 n = vfp_get_float(sn); + + pr_debug("VFP: s%u = %08x\n", sn, n); + + vfp_single_unpack(&vsn, n); + if (vsn.exponent == 0 && vsn.significand) + vfp_single_normalise_denormal(&vsn); + + vfp_single_unpack(&vsm, m); + if (vsm.exponent == 0 && vsm.significand) + vfp_single_normalise_denormal(&vsm); + + exceptions = vfp_single_multiply(&vsd, &vsn, &vsm, fpscr); + return vfp_single_normaliseround(sd, &vsd, fpscr, exceptions, "fmul"); +} + +/* + * sd = -(sn * sm) + */ +static u32 vfp_single_fnmul(int sd, int sn, s32 m, u32 fpscr) +{ + struct vfp_single vsd, vsn, vsm; + u32 exceptions; + s32 n = vfp_get_float(sn); + + pr_debug("VFP: s%u = %08x\n", sn, n); + + vfp_single_unpack(&vsn, n); + if (vsn.exponent == 0 && vsn.significand) + vfp_single_normalise_denormal(&vsn); + + vfp_single_unpack(&vsm, m); + if (vsm.exponent == 0 && vsm.significand) + vfp_single_normalise_denormal(&vsm); + + exceptions = vfp_single_multiply(&vsd, &vsn, &vsm, fpscr); + vsd.sign = vfp_sign_negate(vsd.sign); + return vfp_single_normaliseround(sd, &vsd, fpscr, exceptions, "fnmul"); +} + +/* + * sd = sn + sm + */ +static u32 vfp_single_fadd(int sd, int sn, s32 m, u32 fpscr) +{ + struct vfp_single vsd, vsn, vsm; + u32 exceptions; + s32 n = vfp_get_float(sn); + + pr_debug("VFP: s%u = %08x\n", sn, n); + + /* + * Unpack and normalise denormals. + */ + vfp_single_unpack(&vsn, n); + if (vsn.exponent == 0 && vsn.significand) + vfp_single_normalise_denormal(&vsn); + + vfp_single_unpack(&vsm, m); + if (vsm.exponent == 0 && vsm.significand) + vfp_single_normalise_denormal(&vsm); + + exceptions = vfp_single_add(&vsd, &vsn, &vsm, fpscr); + + return vfp_single_normaliseround(sd, &vsd, fpscr, exceptions, "fadd"); +} + +/* + * sd = sn - sm + */ +static u32 vfp_single_fsub(int sd, int sn, s32 m, u32 fpscr) +{ + /* + * Subtraction is addition with one sign inverted. + */ + return vfp_single_fadd(sd, sn, vfp_single_packed_negate(m), fpscr); +} + +/* + * sd = sn / sm + */ +static u32 vfp_single_fdiv(int sd, int sn, s32 m, u32 fpscr) +{ + struct vfp_single vsd, vsn, vsm; + u32 exceptions = 0; + s32 n = vfp_get_float(sn); + int tm, tn; + + pr_debug("VFP: s%u = %08x\n", sn, n); + + vfp_single_unpack(&vsn, n); + vfp_single_unpack(&vsm, m); + + vsd.sign = vsn.sign ^ vsm.sign; + + tn = vfp_single_type(&vsn); + tm = vfp_single_type(&vsm); + + /* + * Is n a NAN? + */ + if (tn & VFP_NAN) + goto vsn_nan; + + /* + * Is m a NAN? + */ + if (tm & VFP_NAN) + goto vsm_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 exception + */ + 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_single_normalise_denormal(&vsn); + if (tm & VFP_DENORMAL) + vfp_single_normalise_denormal(&vsm); + + /* + * Ok, we have two numbers, we can perform division. + */ + vsd.exponent = vsn.exponent - vsm.exponent + 127 - 1; + vsm.significand <<= 1; + if (vsm.significand <= (2 * vsn.significand)) { + vsn.significand >>= 1; + vsd.exponent++; + } + vsd.significand = ((u64)vsn.significand << 32) / vsm.significand; + if ((vsd.significand & 0x3f) == 0) + vsd.significand |= ((u64)vsm.significand * vsd.significand != (u64)vsn.significand << 32); + + return vfp_single_normaliseround(sd, &vsd, fpscr, 0, "fdiv"); + + vsn_nan: + exceptions = vfp_propagate_nan(&vsd, &vsn, &vsm, fpscr); + pack: + vfp_put_float(sd, vfp_single_pack(&vsd)); + return exceptions; + + vsm_nan: + exceptions = vfp_propagate_nan(&vsd, &vsm, &vsn, fpscr); + goto pack; + + zero: + vsd.exponent = 0; + vsd.significand = 0; + goto pack; + + divzero: + exceptions = FPSCR_DZC; + infinity: + vsd.exponent = 255; + vsd.significand = 0; + goto pack; + + invalid: + vfp_put_float(sd, vfp_single_pack(&vfp_single_default_qnan)); + return FPSCR_IOC; +} + +static u32 (* const fop_fns[16])(int sd, int sn, s32 m, u32 fpscr) = { + [FOP_TO_IDX(FOP_FMAC)] = vfp_single_fmac, + [FOP_TO_IDX(FOP_FNMAC)] = vfp_single_fnmac, + [FOP_TO_IDX(FOP_FMSC)] = vfp_single_fmsc, + [FOP_TO_IDX(FOP_FNMSC)] = vfp_single_fnmsc, + [FOP_TO_IDX(FOP_FMUL)] = vfp_single_fmul, + [FOP_TO_IDX(FOP_FNMUL)] = vfp_single_fnmul, + [FOP_TO_IDX(FOP_FADD)] = vfp_single_fadd, + [FOP_TO_IDX(FOP_FSUB)] = vfp_single_fsub, + [FOP_TO_IDX(FOP_FDIV)] = vfp_single_fdiv, +}; + +#define FREG_BANK(x) ((x) & 0x18) +#define FREG_IDX(x) ((x) & 7) + +u32 vfp_single_cpdo(u32 inst, u32 fpscr) +{ + u32 op = inst & FOP_MASK; + u32 exceptions = 0; + unsigned int sd = vfp_get_sd(inst); + unsigned int sn = vfp_get_sn(inst); + unsigned int sm = vfp_get_sm(inst); + unsigned int vecitr, veclen, vecstride; + u32 (*fop)(int, int, s32, u32); + + veclen = fpscr & FPSCR_LENGTH_MASK; + vecstride = 1 + ((fpscr & FPSCR_STRIDE_MASK) == FPSCR_STRIDE_MASK); + + /* + * If destination bank is zero, vector length is always '1'. + * ARM DDI0100F C5.1.3, C5.3.2. + */ + if (FREG_BANK(sd) == 0) + veclen = 0; + + pr_debug("VFP: vecstride=%u veclen=%u\n", vecstride, + (veclen >> FPSCR_LENGTH_BIT) + 1); + + fop = (op == FOP_EXT) ? fop_extfns[sn] : fop_fns[FOP_TO_IDX(op)]; + if (!fop) + goto invalid; + + for (vecitr = 0; vecitr <= veclen; vecitr += 1 << FPSCR_LENGTH_BIT) { + s32 m = vfp_get_float(sm); + u32 except; + + if (op == FOP_EXT) + pr_debug("VFP: itr%d (s%u) = op[%u] (s%u=%08x)\n", + vecitr >> FPSCR_LENGTH_BIT, sd, sn, sm, m); + else + pr_debug("VFP: itr%d (s%u) = (s%u) op[%u] (s%u=%08x)\n", + vecitr >> FPSCR_LENGTH_BIT, sd, sn, + FOP_TO_IDX(op), sm, m); + + except = fop(sd, sn, m, fpscr); + pr_debug("VFP: itr%d: exceptions=%08x\n", + vecitr >> FPSCR_LENGTH_BIT, except); + + exceptions |= except; + + /* + * This ensures that comparisons only operate on scalars; + * comparisons always return with one FPSCR status bit set. + */ + if (except & (FPSCR_N|FPSCR_Z|FPSCR_C|FPSCR_V)) + break; + + /* + * CHECK: It appears to be undefined whether we stop when + * we encounter an exception. We continue. + */ + + sd = FREG_BANK(sd) + ((FREG_IDX(sd) + vecstride) & 7); + sn = FREG_BANK(sn) + ((FREG_IDX(sn) + vecstride) & 7); + if (FREG_BANK(sm) != 0) + sm = FREG_BANK(sm) + ((FREG_IDX(sm) + vecstride) & 7); + } + return exceptions; + + invalid: + return (u32)-1; +} |
