MIPS R6 introduced the following instruction:
Floating Point Fused Multiply Add:
MADDF.fmt To perform a fused multiply-add of FP values.
MADDF.fmt: FPR[fd] = FPR[fd] + (FPR[fs] x FPR[ft])
Signed-off-by: Markos Chandras <markos.chandras@xxxxxxxxxx>
---
arch/mips/math-emu/Makefile | 4 +-
arch/mips/math-emu/cp1emu.c | 26 +++++
arch/mips/math-emu/dp_maddf.c | 265 ++++++++++++++++++++++++++++++++++++++++++
arch/mips/math-emu/ieee754.h | 5 +
arch/mips/math-emu/sp_maddf.c | 255 ++++++++++++++++++++++++++++++++++++++++
5 files changed, 553 insertions(+), 2 deletions(-)
create mode 100644 arch/mips/math-emu/dp_maddf.c
create mode 100644 arch/mips/math-emu/sp_maddf.c
diff --git a/arch/mips/math-emu/Makefile b/arch/mips/math-emu/Makefile
index 2e5f96275c38..c40816f86a7a 100644
--- a/arch/mips/math-emu/Makefile
+++ b/arch/mips/math-emu/Makefile
@@ -4,9 +4,9 @@
obj-y += cp1emu.o ieee754dp.o ieee754sp.o ieee754.o \
dp_div.o dp_mul.o dp_sub.o dp_add.o dp_fsp.o dp_cmp.o dp_simple.o \
- dp_tint.o dp_fint.o \
+ dp_tint.o dp_fint.o dp_maddf.o \
sp_div.o sp_mul.o sp_sub.o sp_add.o sp_fdp.o sp_cmp.o sp_simple.o \
- sp_tint.o sp_fint.o \
+ sp_tint.o sp_fint.o sp_maddf.o \
dsemul.o
lib-y += ieee754d.o \
diff --git a/arch/mips/math-emu/cp1emu.c b/arch/mips/math-emu/cp1emu.c
index 66d9a78d03ad..68646fa563d8 100644
--- a/arch/mips/math-emu/cp1emu.c
+++ b/arch/mips/math-emu/cp1emu.c
@@ -1747,6 +1747,19 @@ static int fpu_emu(struct pt_regs *xcp, struct mips_fpu_struct *ctx,
rv.w = 0;
break;
+ case fmaddf_op: {
+ union ieee754sp ft, fs, fd;
+
+ if (!cpu_has_mips_r6)
+ return SIGILL;
+
+ SPFROMREG(ft, MIPSInst_FT(ir));
+ SPFROMREG(fs, MIPSInst_FS(ir));
+ SPFROMREG(fd, MIPSInst_FD(ir));
+ rv.s = ieee754sp_maddf(fd, fs, ft);
+ break;
+ }
+
case fabs_op:
handler.u = ieee754sp_abs;
goto scopuop;
@@ -1967,6 +1980,19 @@ copcsr:
rv.l = 0;
break;
+ case fmaddf_op: {
+ union ieee754dp ft, fs, fd;
+
+ if (!cpu_has_mips_r6)
+ return SIGILL;
+
+ DPFROMREG(ft, MIPSInst_FT(ir));
+ DPFROMREG(fs, MIPSInst_FS(ir));
+ DPFROMREG(fd, MIPSInst_FD(ir));
+ rv.d = ieee754dp_maddf(fd, fs, ft);
+ break;
+ }
+
case fabs_op:
handler.u = ieee754dp_abs;
goto dcopuop;
diff --git a/arch/mips/math-emu/dp_maddf.c b/arch/mips/math-emu/dp_maddf.c
new file mode 100644
index 000000000000..119eda9fa1ea
--- /dev/null
+++ b/arch/mips/math-emu/dp_maddf.c
@@ -0,0 +1,265 @@
+/*
+ * IEEE754 floating point arithmetic
+ * double precision: MADDF.f (Fused Multiply Add)
+ * MADDF.fmt: FPR[fd] = FPR[fd] + (FPR[fs] x FPR[ft])
+ *
+ * MIPS floating point support
+ * Copyright (C) 2015 Imagination Technologies, Ltd.
+ * Author: Markos Chandras <markos.chandras@xxxxxxxxxx>
+ *
+ * This program is free software; you can distribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; version 2 of the License.
+ */
+
+#include "ieee754dp.h"
+
+union ieee754dp ieee754dp_maddf(union ieee754dp z, union ieee754dp x,
+ union ieee754dp y)
+{
+ int re;
+ int rs;
+ u64 rm;
+ unsigned lxm;
+ unsigned hxm;
+ unsigned lym;
+ unsigned hym;
+ u64 lrm;
+ u64 hrm;
+ u64 t;
+ u64 at;
+ int s;
+
+ COMPXDP;
+ COMPYDP;
+
+ u64 zm; int ze; int zs __maybe_unused; int zc;
+
+ EXPLODEXDP;
+ EXPLODEYDP;
+ EXPLODEDP(z, zc, zs, ze, zm)
+
+ FLUSHXDP;
+ FLUSHYDP;
+ FLUSHDP(z, zc, zs, ze, zm);
+
+ ieee754_clearcx();
+
+ switch (zc) {
+ case IEEE754_CLASS_SNAN:
+ ieee754_setcx(IEEE754_INVALID_OPERATION);
+ return ieee754dp_nanxcpt(z);
+ case IEEE754_CLASS_DNORM:
+ DPDNORMx(zm, ze);
+ /* QNAN is handled separately below */
+ }
+
+ switch (CLPAIR(xc, yc)) {
+ case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
+ case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
+ case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
+ case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
+ case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
+ return ieee754dp_nanxcpt(y);
+
+ case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
+ case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
+ case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
+ case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
+ case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
+ case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
+ return ieee754dp_nanxcpt(x);
+
+ case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
+ case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
+ case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
+ case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
+ return y;
+
+ case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
+ case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
+ case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
+ case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
+ case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
+ return x;
+
+
+ /*
+ * Infinity handling
+ */
+ case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
+ case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
+ if (zc == IEEE754_CLASS_QNAN)
+ return z;
+ ieee754_setcx(IEEE754_INVALID_OPERATION);
+ return ieee754dp_indef();
+
+ case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
+ case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
+ case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
+ case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
+ case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
+ if (zc == IEEE754_CLASS_QNAN)
+ return z;
+ return ieee754dp_inf(xs ^ ys);
+
+ case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
+ case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
+ case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
+ case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
+ case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
+ if (zc == IEEE754_CLASS_INF)
+ return ieee754dp_inf(zs);
+ /* Multiplication is 0 so just return z */
+ return z;
+
+ case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
+ DPDNORMX;
+
+ case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
+ if (zc == IEEE754_CLASS_QNAN)
+ return z;
+ else if (zc == IEEE754_CLASS_INF)
+ return ieee754dp_inf(zs);
+ DPDNORMY;
+ break;
+
+ case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
+ if (zc == IEEE754_CLASS_QNAN)
+ return z;
+ else if (zc == IEEE754_CLASS_INF)
+ return ieee754dp_inf(zs);
+ DPDNORMX;
+ break;
+
+ case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM):
+ if (zc == IEEE754_CLASS_QNAN)
+ return z;
+ else if (zc == IEEE754_CLASS_INF)
+ return ieee754dp_inf(zs);
+ /* fall through to real computations */
+ }
+
+ /* Finally get to do some computation */
+
+ /*
+ * Do the multiplication bit first
+ *
+ * rm = xm * ym, re = xe + ye basically
+ *
+ * At this point xm and ym should have been normalized.
+ */
+ assert(xm & DP_HIDDEN_BIT);
+ assert(ym & DP_HIDDEN_BIT);
+
+ re = xe + ye;
+ rs = xs ^ ys;
+
+ /* shunt to top of word */
+ xm <<= 64 - (DP_FBITS + 1);
+ ym <<= 64 - (DP_FBITS + 1);
+
+ /*
+ * Multiply 32 bits xm, ym to give high 32 bits rm with stickness.
+ */
+
+ /* 32 * 32 => 64 */
+#define DPXMULT(x, y) ((u64)(x) * (u64)y)
+
+ lxm = xm;
+ hxm = xm >> 32;
+ lym = ym;
+ hym = ym >> 32;
+
+ lrm = DPXMULT(lxm, lym);
+ hrm = DPXMULT(hxm, hym);
+
+ t = DPXMULT(lxm, hym);
+
+ at = lrm + (t << 32);
+ hrm += at < lrm;
+ lrm = at;
+
+ hrm = hrm + (t >> 32);
+
+ t = DPXMULT(hxm, lym);
+
+ at = lrm + (t << 32);
+ hrm += at < lrm;
+ lrm = at;
+
+ hrm = hrm + (t >> 32);
+
+ rm = hrm | (lrm != 0);
+
+ /*
+ * Sticky shift down to normal rounding precision.
+ */
+ if ((s64) rm < 0) {
+ rm = (rm >> (64 - (DP_FBITS + 1 + 3))) |
+ ((rm << (DP_FBITS + 1 + 3)) != 0);
+ re++;
+ } else {
+ rm = (rm >> (64 - (DP_FBITS + 1 + 3 + 1))) |
+ ((rm << (DP_FBITS + 1 + 3 + 1)) != 0);
+ }
+ assert(rm & (DP_HIDDEN_BIT << 3));
+
+ /* And now the addition */
+ assert(zm & DP_HIDDEN_BIT);
+
+ /*
+ * Provide guard,round and stick bit space.
+ */
+ zm <<= 3;
+
+ if (ze > re) {
+ /*
+ * Have to shift y fraction right to align.
+ */
+ s = ze - re;
+ rm = XDPSRS(rm, s);
+ re += s;
+ } else if (re > ze) {
+ /*
+ * Have to shift x fraction right to align.
+ */
+ s = re - ze;
+ zm = XDPSRS(zm, s);
+ ze += s;
+ }
+ assert(ze == re);
+ assert(ze <= DP_EMAX);
+
+ if (zs == rs) {
+ /*
+ * Generate 28 bit result of adding two 27 bit numbers
+ * leaving result in xm, xs and xe.
+ */
+ zm = zm + rm;
+
+ if (zm >> (DP_FBITS + 1 + 3)) { /* carry out */
+ zm = XDPSRS1(zm);
+ ze++;
+ }
+ } else {
+ if (zm >= rm) {
+ zm = zm - rm;
+ } else {
+ zm = rm - zm;
+ zs = rs;
+ }
+ if (zm == 0)
+ return ieee754dp_zero(ieee754_csr.rm == FPU_CSR_RD);
+
+ /*
+ * Normalize to rounding precision.
+ */
+ while ((zm >> (DP_FBITS + 3)) == 0) {
+ zm <<= 1;
+ ze--;
+ }
+ }
+
+ return ieee754dp_format(zs, ze, zm);
+}
diff --git a/arch/mips/math-emu/ieee754.h b/arch/mips/math-emu/ieee754.h
index a5ca108ce467..4e025f9e220c 100644
--- a/arch/mips/math-emu/ieee754.h
+++ b/arch/mips/math-emu/ieee754.h
@@ -75,6 +75,9 @@ int ieee754sp_cmp(union ieee754sp x, union ieee754sp y, int cop, int sig);
union ieee754sp ieee754sp_sqrt(union ieee754sp x);
+union ieee754sp ieee754sp_maddf(union ieee754sp z, union ieee754sp x,
+ union ieee754sp y);
+
/*
* double precision (often aka double)
*/
@@ -99,6 +102,8 @@ int ieee754dp_cmp(union ieee754dp x, union ieee754dp y, int cop, int sig);
union ieee754dp ieee754dp_sqrt(union ieee754dp x);
+union ieee754dp ieee754dp_maddf(union ieee754dp z, union ieee754dp x,
+ union ieee754dp y);
/* 5 types of floating point number
diff --git a/arch/mips/math-emu/sp_maddf.c b/arch/mips/math-emu/sp_maddf.c
new file mode 100644
index 000000000000..dd1dd83e34eb
--- /dev/null
+++ b/arch/mips/math-emu/sp_maddf.c
@@ -0,0 +1,255 @@
+/*
+ * IEEE754 floating point arithmetic
+ * single precision: MADDF.f (Fused Multiply Add)
+ * MADDF.fmt: FPR[fd] = FPR[fd] + (FPR[fs] x FPR[ft])
+ *
+ * MIPS floating point support
+ * Copyright (C) 2015 Imagination Technologies, Ltd.
+ * Author: Markos Chandras <markos.chandras@xxxxxxxxxx>
+ *
+ * This program is free software; you can distribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; version 2 of the License.
+ */
+
+#include "ieee754sp.h"
+
+union ieee754sp ieee754sp_maddf(union ieee754sp z, union ieee754sp x,
+ union ieee754sp y)
+{
+ int re;
+ int rs;
+ unsigned rm;
+ unsigned short lxm;
+ unsigned short hxm;
+ unsigned short lym;
+ unsigned short hym;
+ unsigned lrm;
+ unsigned hrm;
+ unsigned t;
+ unsigned at;
+ int s;
+
+ COMPXSP;
+ COMPYSP;
+ u32 zm; int ze; int zs __maybe_unused; int zc;
+
+ EXPLODEXSP;
+ EXPLODEYSP;
+ EXPLODESP(z, zc, zs, ze, zm)
+
+ FLUSHXSP;
+ FLUSHYSP;
+ FLUSHSP(z, zc, zs, ze, zm);
+
+ ieee754_clearcx();
+
+ switch (zc) {
+ case IEEE754_CLASS_SNAN:
+ ieee754_setcx(IEEE754_INVALID_OPERATION);
+ return ieee754sp_nanxcpt(z);
+ case IEEE754_CLASS_DNORM:
+ SPDNORMx(zm, ze);
+ /* QNAN is handled separately below */
+ }
+
+ switch (CLPAIR(xc, yc)) {
+ case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
+ case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
+ case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
+ case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
+ case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
+ return ieee754sp_nanxcpt(y);
+
+ case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
+ case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
+ case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
+ case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
+ case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
+ case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
+ return ieee754sp_nanxcpt(x);
+
+ case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
+ case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
+ case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
+ case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
+ return y;
+
+ case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
+ case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
+ case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
+ case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
+ case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
+ return x;
+
+ /*
+ * Infinity handling
+ */
+ case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
+ case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
+ if (zc == IEEE754_CLASS_QNAN)
+ return z;
+ ieee754_setcx(IEEE754_INVALID_OPERATION);
+ return ieee754sp_indef();
+
+ case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
+ case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
+ case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
+ case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
+ case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
+ if (zc == IEEE754_CLASS_QNAN)
+ return z;
+ return ieee754sp_inf(xs ^ ys);
+
+ case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
+ case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
+ case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
+ case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
+ case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
+ if (zc == IEEE754_CLASS_INF)
+ return ieee754sp_inf(zs);
+ /* Multiplication is 0 so just return z */
+ return z;
+
+ case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
+ SPDNORMX;
+
+ case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
+ if (zc == IEEE754_CLASS_QNAN)
+ return z;
+ else if (zc == IEEE754_CLASS_INF)
+ return ieee754sp_inf(zs);
+ SPDNORMY;
+ break;
+
+ case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
+ if (zc == IEEE754_CLASS_QNAN)
+ return z;
+ else if (zc == IEEE754_CLASS_INF)
+ return ieee754sp_inf(zs);
+ SPDNORMX;
+ break;
+
+ case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM):
+ if (zc == IEEE754_CLASS_QNAN)
+ return z;
+ else if (zc == IEEE754_CLASS_INF)
+ return ieee754sp_inf(zs);
+ /* fall through to real computations */
+ }
+
+ /* Finally get to do some computation */
+
+ /*
+ * Do the multiplication bit first
+ *
+ * rm = xm * ym, re = xe + ye basically
+ *
+ * At this point xm and ym should have been normalized.
+ */
+
+ /* rm = xm * ym, re = xe+ye basically */
+ assert(xm & SP_HIDDEN_BIT);
+ assert(ym & SP_HIDDEN_BIT);
+
+ re = xe + ye;
+ rs = xs ^ ys;
+
+ /* shunt to top of word */
+ xm <<= 32 - (SP_FBITS + 1);
+ ym <<= 32 - (SP_FBITS + 1);
+
+ /*
+ * Multiply 32 bits xm, ym to give high 32 bits rm with stickness.
+ */
+ lxm = xm & 0xffff;
+ hxm = xm >> 16;
+ lym = ym & 0xffff;
+ hym = ym >> 16;
+
+ lrm = lxm * lym; /* 16 * 16 => 32 */
+ hrm = hxm * hym; /* 16 * 16 => 32 */
+
+ t = lxm * hym; /* 16 * 16 => 32 */
+ at = lrm + (t << 16);
+ hrm += at < lrm;
+ lrm = at;
+ hrm = hrm + (t >> 16);
+
+ t = hxm * lym; /* 16 * 16 => 32 */
+ at = lrm + (t << 16);
+ hrm += at < lrm;
+ lrm = at;
+ hrm = hrm + (t >> 16);
+
+ rm = hrm | (lrm != 0);
+
+ /*
+ * Sticky shift down to normal rounding precision.
+ */
+ if ((int) rm < 0) {
+ rm = (rm >> (32 - (SP_FBITS + 1 + 3))) |
+ ((rm << (SP_FBITS + 1 + 3)) != 0);
+ re++;
+ } else {
+ rm = (rm >> (32 - (SP_FBITS + 1 + 3 + 1))) |
+ ((rm << (SP_FBITS + 1 + 3 + 1)) != 0);
+ }
+ assert(rm & (SP_HIDDEN_BIT << 3));
+
+ /* And now the addition */
+
+ assert(zm & SP_HIDDEN_BIT);
+
+ /*
+ * Provide guard,round and stick bit space.
+ */
+ zm <<= 3;
+
+ if (ze > re) {
+ /*
+ * Have to shift y fraction right to align.
+ */
+ s = ze - re;
+ SPXSRSYn(s);
+ } else if (re > ze) {
+ /*
+ * Have to shift x fraction right to align.
+ */
+ s = re - ze;
+ SPXSRSYn(s);
+ }
+ assert(ze == re);
+ assert(ze <= SP_EMAX);
+
+ if (zs == rs) {
+ /*
+ * Generate 28 bit result of adding two 27 bit numbers
+ * leaving result in zm, zs and ze.
+ */
+ zm = zm + rm;
+
+ if (zm >> (SP_FBITS + 1 + 3)) { /* carry out */
+ SPXSRSX1();
+ }
+ } else {
+ if (zm >= rm) {
+ zm = zm - rm;
+ } else {
+ zm = rm - zm;
+ zs = rs;
+ }
+ if (zm == 0)
+ return ieee754sp_zero(ieee754_csr.rm == FPU_CSR_RD);
+
+ /*
+ * Normalize in extended single precision
+ */
+ while ((zm >> (SP_MBITS + 3)) == 0) {
+ zm <<= 1;
+ ze--;
+ }
+
+ }
+ return ieee754sp_format(zs, ze, zm);
+}
--
2.5.0
