Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 172 insertions, 0 deletions

diff --git a/arch/mips/math-emu/dp_sub.c b/arch/mips/math-emu/dp_sub.c
new file mode 100644
index 000000000..08474ad2a
--- /dev/null
+++ b/arch/mips/math-emu/dp_sub.c
@@ -0,0 +1,172 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* IEEE754 floating point arithmetic
+ * double precision: common utilities
+ */
+/*
+ * MIPS floating point support
+ * Copyright (C) 1994-2000 Algorithmics Ltd.
+ */
+
+#include "ieee754dp.h"
+
+union ieee754dp ieee754dp_sub(union ieee754dp x, union ieee754dp y)
+{
+	int s;
+
+	COMPXDP;
+	COMPYDP;
+
+	EXPLODEXDP;
+	EXPLODEYDP;
+
+	ieee754_clearcx();
+
+	FLUSHXDP;
+	FLUSHYDP;
+
+	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_INF):
+		if (xs != ys)
+			return x;
+		ieee754_setcx(IEEE754_INVALID_OPERATION);
+		return ieee754dp_indef();
+
+	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
+	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
+	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
+		return ieee754dp_inf(ys ^ 1);
+
+	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
+	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
+	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
+		return x;
+
+	/*
+	 * Zero handling
+	 */
+	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
+		if (xs != ys)
+			return x;
+		else
+			return ieee754dp_zero(ieee754_csr.rm == FPU_CSR_RD);
+
+	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
+	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
+		return x;
+
+	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
+	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
+		/* quick fix up */
+		DPSIGN(y) ^= 1;
+		return y;
+
+	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
+		DPDNORMX;
+		fallthrough;
+	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
+		/* normalize ym,ye */
+		DPDNORMY;
+		break;
+
+	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
+		/* normalize xm,xe */
+		DPDNORMX;
+		break;
+
+	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM):
+		break;
+	}
+	/* flip sign of y and handle as add */
+	ys ^= 1;
+
+	assert(xm & DP_HIDDEN_BIT);
+	assert(ym & DP_HIDDEN_BIT);
+
+
+	/* provide guard,round and stick bit dpace */
+	xm <<= 3;
+	ym <<= 3;
+
+	if (xe > ye) {
+		/*
+		 * Have to shift y fraction right to align
+		 */
+		s = xe - ye;
+		ym = XDPSRS(ym, s);
+		ye += s;
+	} else if (ye > xe) {
+		/*
+		 * Have to shift x fraction right to align
+		 */
+		s = ye - xe;
+		xm = XDPSRS(xm, s);
+		xe += s;
+	}
+	assert(xe == ye);
+	assert(xe <= DP_EMAX);
+
+	if (xs == ys) {
+		/* generate 28 bit result of adding two 27 bit numbers
+		 */
+		xm = xm + ym;
+
+		if (xm >> (DP_FBITS + 1 + 3)) { /* carry out */
+			xm = XDPSRS1(xm);	/* shift preserving sticky */
+			xe++;
+		}
+	} else {
+		if (xm >= ym) {
+			xm = xm - ym;
+		} else {
+			xm = ym - xm;
+			xs = ys;
+		}
+		if (xm == 0) {
+			if (ieee754_csr.rm == FPU_CSR_RD)
+				return ieee754dp_zero(1);	/* round negative inf. => sign = -1 */
+			else
+				return ieee754dp_zero(0);	/* other round modes   => sign = 1 */
+		}
+
+		/* normalize to rounding precision
+		 */
+		while ((xm >> (DP_FBITS + 3)) == 0) {
+			xm <<= 1;
+			xe--;
+		}
+	}
+
+	return ieee754dp_format(xs, xe, xm);
+}