Fixed MTP to work with TWRP

arch/mips/math-emu/ieee754dp.c

@@ -0,0 +1,205 @@
+/* IEEE754 floating point arithmetic
+ * double precision: common utilities
+ */
+/*
+ * MIPS floating point support
+ * Copyright (C) 1994-2000 Algorithmics Ltd.
+ *
+ *  This program is free software; you can distribute it and/or modify it
+ *  under the terms of the GNU General Public License (Version 2) as
+ *  published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA.
+ */
+
+#include <linux/compiler.h>
+
+#include "ieee754dp.h"
+
+int ieee754dp_class(union ieee754dp x)
+{
+	COMPXDP;
+	EXPLODEXDP;
+	return xc;
+}
+
+int ieee754dp_isnan(union ieee754dp x)
+{
+	return ieee754dp_class(x) >= IEEE754_CLASS_SNAN;
+}
+
+static inline int ieee754dp_issnan(union ieee754dp x)
+{
+	assert(ieee754dp_isnan(x));
+	return ((DPMANT(x) & DP_MBIT(DP_FBITS-1)) == DP_MBIT(DP_FBITS-1));
+}
+
+
+union ieee754dp __cold ieee754dp_nanxcpt(union ieee754dp r)
+{
+	assert(ieee754dp_isnan(r));
+
+	if (!ieee754dp_issnan(r))	/* QNAN does not cause invalid op !! */
+		return r;
+
+	if (!ieee754_setandtestcx(IEEE754_INVALID_OPERATION)) {
+		/* not enabled convert to a quiet NaN */
+		DPMANT(r) &= (~DP_MBIT(DP_FBITS-1));
+		if (ieee754dp_isnan(r))
+			return r;
+		else
+			return ieee754dp_indef();
+	}
+
+	return r;
+}
+
+static u64 ieee754dp_get_rounding(int sn, u64 xm)
+{
+	/* inexact must round of 3 bits
+	 */
+	if (xm & (DP_MBIT(3) - 1)) {
+		switch (ieee754_csr.rm) {
+		case FPU_CSR_RZ:
+			break;
+		case FPU_CSR_RN:
+			xm += 0x3 + ((xm >> 3) & 1);
+			/* xm += (xm&0x8)?0x4:0x3 */
+			break;
+		case FPU_CSR_RU:	/* toward +Infinity */
+			if (!sn)	/* ?? */
+				xm += 0x8;
+			break;
+		case FPU_CSR_RD:	/* toward -Infinity */
+			if (sn) /* ?? */
+				xm += 0x8;
+			break;
+		}
+	}
+	return xm;
+}
+
+
+/* generate a normal/denormal number with over,under handling
+ * sn is sign
+ * xe is an unbiased exponent
+ * xm is 3bit extended precision value.
+ */
+union ieee754dp ieee754dp_format(int sn, int xe, u64 xm)
+{
+	assert(xm);		/* we don't gen exact zeros (probably should) */
+
+	assert((xm >> (DP_FBITS + 1 + 3)) == 0);	/* no execess */
+	assert(xm & (DP_HIDDEN_BIT << 3));
+
+	if (xe < DP_EMIN) {
+		/* strip lower bits */
+		int es = DP_EMIN - xe;
+
+		if (ieee754_csr.nod) {
+			ieee754_setcx(IEEE754_UNDERFLOW);
+			ieee754_setcx(IEEE754_INEXACT);
+
+			switch(ieee754_csr.rm) {
+			case FPU_CSR_RN:
+			case FPU_CSR_RZ:
+				return ieee754dp_zero(sn);
+			case FPU_CSR_RU:    /* toward +Infinity */
+				if (sn == 0)
+					return ieee754dp_min(0);
+				else
+					return ieee754dp_zero(1);
+			case FPU_CSR_RD:    /* toward -Infinity */
+				if (sn == 0)
+					return ieee754dp_zero(0);
+				else
+					return ieee754dp_min(1);
+			}
+		}
+
+		if (xe == DP_EMIN - 1 &&
+		    ieee754dp_get_rounding(sn, xm) >> (DP_FBITS + 1 + 3))
+		{
+			/* Not tiny after rounding */
+			ieee754_setcx(IEEE754_INEXACT);
+			xm = ieee754dp_get_rounding(sn, xm);
+			xm >>= 1;
+			/* Clear grs bits */
+			xm &= ~(DP_MBIT(3) - 1);
+			xe++;
+		}
+		else {
+			/* sticky right shift es bits
+			 */
+			xm = XDPSRS(xm, es);
+			xe += es;
+			assert((xm & (DP_HIDDEN_BIT << 3)) == 0);
+			assert(xe == DP_EMIN);
+		}
+	}
+	if (xm & (DP_MBIT(3) - 1)) {
+		ieee754_setcx(IEEE754_INEXACT);
+		if ((xm & (DP_HIDDEN_BIT << 3)) == 0) {
+			ieee754_setcx(IEEE754_UNDERFLOW);
+		}
+
+		/* inexact must round of 3 bits
+		 */
+		xm = ieee754dp_get_rounding(sn, xm);
+		/* adjust exponent for rounding add overflowing
+		 */
+		if (xm >> (DP_FBITS + 3 + 1)) {
+			/* add causes mantissa overflow */
+			xm >>= 1;
+			xe++;
+		}
+	}
+	/* strip grs bits */
+	xm >>= 3;
+
+	assert((xm >> (DP_FBITS + 1)) == 0);	/* no execess */
+	assert(xe >= DP_EMIN);
+
+	if (xe > DP_EMAX) {
+		ieee754_setcx(IEEE754_OVERFLOW);
+		ieee754_setcx(IEEE754_INEXACT);
+		/* -O can be table indexed by (rm,sn) */
+		switch (ieee754_csr.rm) {
+		case FPU_CSR_RN:
+			return ieee754dp_inf(sn);
+		case FPU_CSR_RZ:
+			return ieee754dp_max(sn);
+		case FPU_CSR_RU:	/* toward +Infinity */
+			if (sn == 0)
+				return ieee754dp_inf(0);
+			else
+				return ieee754dp_max(1);
+		case FPU_CSR_RD:	/* toward -Infinity */
+			if (sn == 0)
+				return ieee754dp_max(0);
+			else
+				return ieee754dp_inf(1);
+		}
+	}
+	/* gen norm/denorm/zero */
+
+	if ((xm & DP_HIDDEN_BIT) == 0) {
+		/* we underflow (tiny/zero) */
+		assert(xe == DP_EMIN);
+		if (ieee754_csr.mx & IEEE754_UNDERFLOW)
+			ieee754_setcx(IEEE754_UNDERFLOW);
+		return builddp(sn, DP_EMIN - 1 + DP_EBIAS, xm);
+	} else {
+		assert((xm >> (DP_FBITS + 1)) == 0);	/* no execess */
+		assert(xm & DP_HIDDEN_BIT);
+
+		return builddp(sn, xe + DP_EBIAS, xm & ~DP_HIDDEN_BIT);
+	}
+}