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linux/arch/arm/vfp/vfpsingle.c

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/*
* 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/div64.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);
#ifdef DEBUG
pr_debug("VFP: %s: d(s%d)=%08x exceptions=%08x\n", func,
sd, d, exceptions);
#endif
vfp_put_float(d, sd);
}
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_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(vfp_single_packed_abs(m), sd);
return 0;
}
static u32 vfp_single_fcpy(int sd, int unused, s32 m, u32 fpscr)
{
vfp_put_float(m, sd);
return 0;
}
static u32 vfp_single_fneg(int sd, int unused, s32 m, u32 fpscr)
{
vfp_put_float(vfp_single_packed_negate(m), sd);
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;
}
{
u64 v = (u64)a << 31;
do_div(v, z);
return v + (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(vfp_single_pack(vsp), sd);
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_QNAN)
vdd.significand |= VFP_DOUBLE_SIGNIFICAND_QNAN;
goto pack_nan;
} else if (tm & VFP_ZERO)
vdd.exponent = 0;
else
vdd.exponent = vsm.exponent + (1023 - 127);
return vfp_double_normaliseround(dd, &vdd, fpscr, exceptions, "fcvtd");
pack_nan:
vfp_put_double(vfp_double_pack(&vdd), dd);
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(d, sd);
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;
int tm;
vfp_single_unpack(&vsm, m);
vfp_single_dump("VSM", &vsm);
/*
* Do we have a denormalised number?
*/
tm = vfp_single_type(&vsm);
if (vfp_single_type(&vsm) & VFP_DENORMAL)
exceptions |= FPSCR_IDC;
if (tm & VFP_NAN) {
d = 0;
exceptions |= FPSCR_IOC;
} else 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((s32)d, sd);
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 struct op fops_ext[32] = {
[FEXT_TO_IDX(FEXT_FCPY)] = { vfp_single_fcpy, 0 },
[FEXT_TO_IDX(FEXT_FABS)] = { vfp_single_fabs, 0 },
[FEXT_TO_IDX(FEXT_FNEG)] = { vfp_single_fneg, 0 },
[FEXT_TO_IDX(FEXT_FSQRT)] = { vfp_single_fsqrt, 0 },
[FEXT_TO_IDX(FEXT_FCMP)] = { vfp_single_fcmp, OP_SCALAR },
[FEXT_TO_IDX(FEXT_FCMPE)] = { vfp_single_fcmpe, OP_SCALAR },
[FEXT_TO_IDX(FEXT_FCMPZ)] = { vfp_single_fcmpz, OP_SCALAR },
[FEXT_TO_IDX(FEXT_FCMPEZ)] = { vfp_single_fcmpez, OP_SCALAR },
[FEXT_TO_IDX(FEXT_FCVT)] = { vfp_single_fcvtd, OP_SCALAR|OP_DD },
[FEXT_TO_IDX(FEXT_FUITO)] = { vfp_single_fuito, OP_SCALAR },
[FEXT_TO_IDX(FEXT_FSITO)] = { vfp_single_fsito, OP_SCALAR },
[FEXT_TO_IDX(FEXT_FTOUI)] = { vfp_single_ftoui, OP_SCALAR },
[FEXT_TO_IDX(FEXT_FTOUIZ)] = { vfp_single_ftouiz, OP_SCALAR },
[FEXT_TO_IDX(FEXT_FTOSI)] = { vfp_single_ftosi, OP_SCALAR },
[FEXT_TO_IDX(FEXT_FTOSIZ)] = { vfp_single_ftosiz, OP_SCALAR },
};
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++;
}
{
u64 significand = (u64)vsn.significand << 32;
do_div(significand, vsm.significand);
vsd.significand = 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(vfp_single_pack(&vsd), sd);
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(vfp_single_pack(&vfp_single_default_qnan), sd);
return FPSCR_IOC;
}
static struct op fops[16] = {
[FOP_TO_IDX(FOP_FMAC)] = { vfp_single_fmac, 0 },
[FOP_TO_IDX(FOP_FNMAC)] = { vfp_single_fnmac, 0 },
[FOP_TO_IDX(FOP_FMSC)] = { vfp_single_fmsc, 0 },
[FOP_TO_IDX(FOP_FNMSC)] = { vfp_single_fnmsc, 0 },
[FOP_TO_IDX(FOP_FMUL)] = { vfp_single_fmul, 0 },
[FOP_TO_IDX(FOP_FNMUL)] = { vfp_single_fnmul, 0 },
[FOP_TO_IDX(FOP_FADD)] = { vfp_single_fadd, 0 },
[FOP_TO_IDX(FOP_FSUB)] = { vfp_single_fsub, 0 },
[FOP_TO_IDX(FOP_FDIV)] = { vfp_single_fdiv, 0 },
};
#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 dest;
unsigned int sn = vfp_get_sn(inst);
unsigned int sm = vfp_get_sm(inst);
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)];
/*
* fcvtsd takes a dN register number as destination, not sN.
* Technically, if bit 0 of dd is set, this is an invalid
* instruction. However, we ignore this for efficiency.
* It also only operates on scalars.
*/
if (fop->flags & OP_DD)
dest = vfp_get_dd(inst);
else
dest = vfp_get_sd(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) {
s32 m = vfp_get_float(sm);
u32 except;
char type;
type = fop->flags & OP_DD ? 'd' : 's';
if (op == FOP_EXT)
pr_debug("VFP: itr%d (%c%u) = op[%u] (s%u=%08x)\n",
vecitr >> FPSCR_LENGTH_BIT, type, dest, sn,
sm, m);
else
pr_debug("VFP: itr%d (%c%u) = (s%u) op[%u] (s%u=%08x)\n",
vecitr >> FPSCR_LENGTH_BIT, type, dest, sn,
FOP_TO_IDX(op), sm, m);
except = fop->fn(dest, sn, m, 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) & 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;
}
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