1 files changed, 278 insertions, 0 deletions
diff --git a/arch/mips/math-emu/sp_maddf.c b/arch/mips/math-emu/sp_maddf.c
new file mode 100644
index 000000000..473ee222d
--- /dev/null
+++ b/arch/mips/math-emu/sp_maddf.c
@@ -0,0 +1,278 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 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@imgtec.com>
+ */
+
+#include "ieee754sp.h"
+
+
+static union ieee754sp _sp_maddf(union ieee754sp z, union ieee754sp x,
+				 union ieee754sp y, enum maddf_flags flags)
+{
+	int re;
+	int rs;
+	unsigned int rm;
+	u64 rm64;
+	u64 zm64;
+	int s;
+
+	COMPXSP;
+	COMPYSP;
+	COMPZSP;
+
+	EXPLODEXSP;
+	EXPLODEYSP;
+	EXPLODEZSP;
+
+	FLUSHXSP;
+	FLUSHYSP;
+	FLUSHZSP;
+
+	ieee754_clearcx();
+
+	rs = xs ^ ys;
+	if (flags & MADDF_NEGATE_PRODUCT)
+		rs ^= 1;
+	if (flags & MADDF_NEGATE_ADDITION)
+		zs ^= 1;
+
+	/*
+	 * Handle the cases when at least one of x, y or z is a NaN.
+	 * Order of precedence is sNaN, qNaN and z, x, y.
+	 */
+	if (zc == IEEE754_CLASS_SNAN)
+		return ieee754sp_nanxcpt(z);
+	if (xc == IEEE754_CLASS_SNAN)
+		return ieee754sp_nanxcpt(x);
+	if (yc == IEEE754_CLASS_SNAN)
+		return ieee754sp_nanxcpt(y);
+	if (zc == IEEE754_CLASS_QNAN)
+		return z;
+	if (xc == IEEE754_CLASS_QNAN)
+		return x;
+	if (yc == IEEE754_CLASS_QNAN)
+		return y;
+
+	if (zc == IEEE754_CLASS_DNORM)
+		SPDNORMZ;
+	/* ZERO z cases are handled separately below */
+
+	switch (CLPAIR(xc, yc)) {
+
+
+	/*
+	 * Infinity handling
+	 */
+	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
+	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
+		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_INF) && (zs != rs)) {
+			/*
+			 * Cases of addition of infinities with opposite signs
+			 * or subtraction of infinities with same signs.
+			 */
+			ieee754_setcx(IEEE754_INVALID_OPERATION);
+			return ieee754sp_indef();
+		}
+		/*
+		 * z is here either not an infinity, or an infinity having the
+		 * same sign as product (x*y). The result must be an infinity,
+		 * and its sign is determined only by the sign of product (x*y).
+		 */
+		return ieee754sp_inf(rs);
+
+	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);
+		if (zc == IEEE754_CLASS_ZERO) {
+			/* Handle cases +0 + (-0) and similar ones. */
+			if (zs == rs)
+				/*
+				 * Cases of addition of zeros of equal signs
+				 * or subtraction of zeroes of opposite signs.
+				 * The sign of the resulting zero is in any
+				 * such case determined only by the sign of z.
+				 */
+				return z;
+
+			return ieee754sp_zero(ieee754_csr.rm == FPU_CSR_RD);
+		}
+		/* x*y is here 0, and z is not 0, so just return z */
+		return z;
+
+	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
+		SPDNORMX;
+		fallthrough;
+	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
+		if (zc == IEEE754_CLASS_INF)
+			return ieee754sp_inf(zs);
+		SPDNORMY;
+		break;
+
+	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
+		if (zc == IEEE754_CLASS_INF)
+			return ieee754sp_inf(zs);
+		SPDNORMX;
+		break;
+
+	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM):
+		if (zc == IEEE754_CLASS_INF)
+			return ieee754sp_inf(zs);
+		/* continue 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;
+
+	/* Multiple 24 bit xm and ym to give 48 bit results */
+	rm64 = (uint64_t)xm * ym;
+
+	/* Shunt to top of word */
+	rm64 = rm64 << 16;
+
+	/* Put explicit bit at bit 62 if necessary */
+	if ((int64_t) rm64 < 0) {
+		rm64 = rm64 >> 1;
+		re++;
+	}
+
+	assert(rm64 & (1 << 62));
+
+	if (zc == IEEE754_CLASS_ZERO) {
+		/*
+		 * Move explicit bit from bit 62 to bit 26 since the
+		 * ieee754sp_format code expects the mantissa to be
+		 * 27 bits wide (24 + 3 rounding bits).
+		 */
+		rm = XSPSRS64(rm64, (62 - 26));
+		return ieee754sp_format(rs, re, rm);
+	}
+
+	/* Move explicit bit from bit 23 to bit 62 */
+	zm64 = (uint64_t)zm << (62 - 23);
+	assert(zm64 & (1 << 62));
+
+	/* Make the exponents the same */
+	if (ze > re) {
+		/*
+		 * Have to shift r fraction right to align.
+		 */
+		s = ze - re;
+		rm64 = XSPSRS64(rm64, s);
+		re += s;
+	} else if (re > ze) {
+		/*
+		 * Have to shift z fraction right to align.
+		 */
+		s = re - ze;
+		zm64 = XSPSRS64(zm64, s);
+		ze += s;
+	}
+	assert(ze == re);
+	assert(ze <= SP_EMAX);
+
+	/* Do the addition */
+	if (zs == rs) {
+		/*
+		 * Generate 64 bit result by adding two 63 bit numbers
+		 * leaving result in zm64, zs and ze.
+		 */
+		zm64 = zm64 + rm64;
+		if ((int64_t)zm64 < 0) {	/* carry out */
+			zm64 = XSPSRS1(zm64);
+			ze++;
+		}
+	} else {
+		if (zm64 >= rm64) {
+			zm64 = zm64 - rm64;
+		} else {
+			zm64 = rm64 - zm64;
+			zs = rs;
+		}
+		if (zm64 == 0)
+			return ieee754sp_zero(ieee754_csr.rm == FPU_CSR_RD);
+
+		/*
+		 * Put explicit bit at bit 62 if necessary.
+		 */
+		while ((zm64 >> 62) == 0) {
+			zm64 <<= 1;
+			ze--;
+		}
+	}
+
+	/*
+	 * Move explicit bit from bit 62 to bit 26 since the
+	 * ieee754sp_format code expects the mantissa to be
+	 * 27 bits wide (24 + 3 rounding bits).
+	 */
+	zm = XSPSRS64(zm64, (62 - 26));
+
+	return ieee754sp_format(zs, ze, zm);
+}
+
+union ieee754sp ieee754sp_maddf(union ieee754sp z, union ieee754sp x,
+				union ieee754sp y)
+{
+	return _sp_maddf(z, x, y, 0);
+}
+
+union ieee754sp ieee754sp_msubf(union ieee754sp z, union ieee754sp x,
+				union ieee754sp y)
+{
+	return _sp_maddf(z, x, y, MADDF_NEGATE_PRODUCT);
+}
+
+union ieee754sp ieee754sp_madd(union ieee754sp z, union ieee754sp x,
+				union ieee754sp y)
+{
+	return _sp_maddf(z, x, y, 0);
+}
+
+union ieee754sp ieee754sp_msub(union ieee754sp z, union ieee754sp x,
+				union ieee754sp y)
+{
+	return _sp_maddf(z, x, y, MADDF_NEGATE_ADDITION);
+}
+
+union ieee754sp ieee754sp_nmadd(union ieee754sp z, union ieee754sp x,
+				union ieee754sp y)
+{
+	return _sp_maddf(z, x, y, MADDF_NEGATE_PRODUCT|MADDF_NEGATE_ADDITION);
+}
+
+union ieee754sp ieee754sp_nmsub(union ieee754sp z, union ieee754sp x,
+				union ieee754sp y)
+{
+	return _sp_maddf(z, x, y, MADDF_NEGATE_PRODUCT);
+}