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-rw-r--r--arch/mips/math-emu/dp_maddf.c265
1 files changed, 265 insertions, 0 deletions
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
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+++ b/arch/mips/math-emu/dp_maddf.c
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+/*
+ * 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@imgtec.com>
+ *
+ *  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);
+}
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