From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 arch/m68k/math-emu/multi_arith.h | 289 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 289 insertions(+)
 create mode 100644 arch/m68k/math-emu/multi_arith.h

(limited to 'arch/m68k/math-emu/multi_arith.h')

diff --git a/arch/m68k/math-emu/multi_arith.h b/arch/m68k/math-emu/multi_arith.h
new file mode 100644
index 000000000..4b5eb3d85
--- /dev/null
+++ b/arch/m68k/math-emu/multi_arith.h
@@ -0,0 +1,289 @@
+/* multi_arith.h: multi-precision integer arithmetic functions, needed
+   to do extended-precision floating point.
+
+   (c) 1998 David Huggins-Daines.
+
+   Somewhat based on arch/alpha/math-emu/ieee-math.c, which is (c)
+   David Mosberger-Tang.
+
+   You may copy, modify, and redistribute this file under the terms of
+   the GNU General Public License, version 2, or any later version, at
+   your convenience. */
+
+/* Note:
+
+   These are not general multi-precision math routines.  Rather, they
+   implement the subset of integer arithmetic that we need in order to
+   multiply, divide, and normalize 128-bit unsigned mantissae.  */
+
+#ifndef MULTI_ARITH_H
+#define MULTI_ARITH_H
+
+static inline void fp_denormalize(struct fp_ext *reg, unsigned int cnt)
+{
+	reg->exp += cnt;
+
+	switch (cnt) {
+	case 0 ... 8:
+		reg->lowmant = reg->mant.m32[1] << (8 - cnt);
+		reg->mant.m32[1] = (reg->mant.m32[1] >> cnt) |
+				   (reg->mant.m32[0] << (32 - cnt));
+		reg->mant.m32[0] = reg->mant.m32[0] >> cnt;
+		break;
+	case 9 ... 32:
+		reg->lowmant = reg->mant.m32[1] >> (cnt - 8);
+		if (reg->mant.m32[1] << (40 - cnt))
+			reg->lowmant |= 1;
+		reg->mant.m32[1] = (reg->mant.m32[1] >> cnt) |
+				   (reg->mant.m32[0] << (32 - cnt));
+		reg->mant.m32[0] = reg->mant.m32[0] >> cnt;
+		break;
+	case 33 ... 39:
+		asm volatile ("bfextu %1{%2,#8},%0" : "=d" (reg->lowmant)
+			: "m" (reg->mant.m32[0]), "d" (64 - cnt));
+		if (reg->mant.m32[1] << (40 - cnt))
+			reg->lowmant |= 1;
+		reg->mant.m32[1] = reg->mant.m32[0] >> (cnt - 32);
+		reg->mant.m32[0] = 0;
+		break;
+	case 40 ... 71:
+		reg->lowmant = reg->mant.m32[0] >> (cnt - 40);
+		if ((reg->mant.m32[0] << (72 - cnt)) || reg->mant.m32[1])
+			reg->lowmant |= 1;
+		reg->mant.m32[1] = reg->mant.m32[0] >> (cnt - 32);
+		reg->mant.m32[0] = 0;
+		break;
+	default:
+		reg->lowmant = reg->mant.m32[0] || reg->mant.m32[1];
+		reg->mant.m32[0] = 0;
+		reg->mant.m32[1] = 0;
+		break;
+	}
+}
+
+static inline int fp_overnormalize(struct fp_ext *reg)
+{
+	int shift;
+
+	if (reg->mant.m32[0]) {
+		asm ("bfffo %1{#0,#32},%0" : "=d" (shift) : "dm" (reg->mant.m32[0]));
+		reg->mant.m32[0] = (reg->mant.m32[0] << shift) | (reg->mant.m32[1] >> (32 - shift));
+		reg->mant.m32[1] = (reg->mant.m32[1] << shift);
+	} else {
+		asm ("bfffo %1{#0,#32},%0" : "=d" (shift) : "dm" (reg->mant.m32[1]));
+		reg->mant.m32[0] = (reg->mant.m32[1] << shift);
+		reg->mant.m32[1] = 0;
+		shift += 32;
+	}
+
+	return shift;
+}
+
+static inline int fp_addmant(struct fp_ext *dest, struct fp_ext *src)
+{
+	int carry;
+
+	/* we assume here, gcc only insert move and a clr instr */
+	asm volatile ("add.b %1,%0" : "=d,g" (dest->lowmant)
+		: "g,d" (src->lowmant), "0,0" (dest->lowmant));
+	asm volatile ("addx.l %1,%0" : "=d" (dest->mant.m32[1])
+		: "d" (src->mant.m32[1]), "0" (dest->mant.m32[1]));
+	asm volatile ("addx.l %1,%0" : "=d" (dest->mant.m32[0])
+		: "d" (src->mant.m32[0]), "0" (dest->mant.m32[0]));
+	asm volatile ("addx.l %0,%0" : "=d" (carry) : "0" (0));
+
+	return carry;
+}
+
+static inline int fp_addcarry(struct fp_ext *reg)
+{
+	if (++reg->exp == 0x7fff) {
+		if (reg->mant.m64)
+			fp_set_sr(FPSR_EXC_INEX2);
+		reg->mant.m64 = 0;
+		fp_set_sr(FPSR_EXC_OVFL);
+		return 0;
+	}
+	reg->lowmant = (reg->mant.m32[1] << 7) | (reg->lowmant ? 1 : 0);
+	reg->mant.m32[1] = (reg->mant.m32[1] >> 1) |
+			   (reg->mant.m32[0] << 31);
+	reg->mant.m32[0] = (reg->mant.m32[0] >> 1) | 0x80000000;
+
+	return 1;
+}
+
+static inline void fp_submant(struct fp_ext *dest, struct fp_ext *src1,
+			      struct fp_ext *src2)
+{
+	/* we assume here, gcc only insert move and a clr instr */
+	asm volatile ("sub.b %1,%0" : "=d,g" (dest->lowmant)
+		: "g,d" (src2->lowmant), "0,0" (src1->lowmant));
+	asm volatile ("subx.l %1,%0" : "=d" (dest->mant.m32[1])
+		: "d" (src2->mant.m32[1]), "0" (src1->mant.m32[1]));
+	asm volatile ("subx.l %1,%0" : "=d" (dest->mant.m32[0])
+		: "d" (src2->mant.m32[0]), "0" (src1->mant.m32[0]));
+}
+
+#define fp_mul64(desth, destl, src1, src2) ({				\
+	asm ("mulu.l %2,%1:%0" : "=d" (destl), "=d" (desth)		\
+		: "dm" (src1), "0" (src2));				\
+})
+#define fp_div64(quot, rem, srch, srcl, div)				\
+	asm ("divu.l %2,%1:%0" : "=d" (quot), "=d" (rem)		\
+		: "dm" (div), "1" (srch), "0" (srcl))
+#define fp_add64(dest1, dest2, src1, src2) ({				\
+	asm ("add.l %1,%0" : "=d,dm" (dest2)				\
+		: "dm,d" (src2), "0,0" (dest2));			\
+	asm ("addx.l %1,%0" : "=d" (dest1)				\
+		: "d" (src1), "0" (dest1));				\
+})
+#define fp_addx96(dest, src) ({						\
+	/* we assume here, gcc only insert move and a clr instr */	\
+	asm volatile ("add.l %1,%0" : "=d,g" (dest->m32[2])		\
+		: "g,d" (temp.m32[1]), "0,0" (dest->m32[2]));		\
+	asm volatile ("addx.l %1,%0" : "=d" (dest->m32[1])		\
+		: "d" (temp.m32[0]), "0" (dest->m32[1]));		\
+	asm volatile ("addx.l %1,%0" : "=d" (dest->m32[0])		\
+		: "d" (0), "0" (dest->m32[0]));				\
+})
+#define fp_sub64(dest, src) ({						\
+	asm ("sub.l %1,%0" : "=d,dm" (dest.m32[1])			\
+		: "dm,d" (src.m32[1]), "0,0" (dest.m32[1]));		\
+	asm ("subx.l %1,%0" : "=d" (dest.m32[0])			\
+		: "d" (src.m32[0]), "0" (dest.m32[0]));			\
+})
+#define fp_sub96c(dest, srch, srcm, srcl) ({				\
+	char carry;							\
+	asm ("sub.l %1,%0" : "=d,dm" (dest.m32[2])			\
+		: "dm,d" (srcl), "0,0" (dest.m32[2]));			\
+	asm ("subx.l %1,%0" : "=d" (dest.m32[1])			\
+		: "d" (srcm), "0" (dest.m32[1]));			\
+	asm ("subx.l %2,%1; scs %0" : "=d" (carry), "=d" (dest.m32[0])	\
+		: "d" (srch), "1" (dest.m32[0]));			\
+	carry;								\
+})
+
+static inline void fp_multiplymant(union fp_mant128 *dest, struct fp_ext *src1,
+				   struct fp_ext *src2)
+{
+	union fp_mant64 temp;
+
+	fp_mul64(dest->m32[0], dest->m32[1], src1->mant.m32[0], src2->mant.m32[0]);
+	fp_mul64(dest->m32[2], dest->m32[3], src1->mant.m32[1], src2->mant.m32[1]);
+
+	fp_mul64(temp.m32[0], temp.m32[1], src1->mant.m32[0], src2->mant.m32[1]);
+	fp_addx96(dest, temp);
+
+	fp_mul64(temp.m32[0], temp.m32[1], src1->mant.m32[1], src2->mant.m32[0]);
+	fp_addx96(dest, temp);
+}
+
+static inline void fp_dividemant(union fp_mant128 *dest, struct fp_ext *src,
+				 struct fp_ext *div)
+{
+	union fp_mant128 tmp;
+	union fp_mant64 tmp64;
+	unsigned long *mantp = dest->m32;
+	unsigned long fix, rem, first, dummy;
+	int i;
+
+	/* the algorithm below requires dest to be smaller than div,
+	   but both have the high bit set */
+	if (src->mant.m64 >= div->mant.m64) {
+		fp_sub64(src->mant, div->mant);
+		*mantp = 1;
+	} else
+		*mantp = 0;
+	mantp++;
+
+	/* basic idea behind this algorithm: we can't divide two 64bit numbers
+	   (AB/CD) directly, but we can calculate AB/C0, but this means this
+	   quotient is off by C0/CD, so we have to multiply the first result
+	   to fix the result, after that we have nearly the correct result
+	   and only a few corrections are needed. */
+
+	/* C0/CD can be precalculated, but it's an 64bit division again, but
+	   we can make it a bit easier, by dividing first through C so we get
+	   10/1D and now only a single shift and the value fits into 32bit. */
+	fix = 0x80000000;
+	dummy = div->mant.m32[1] / div->mant.m32[0] + 1;
+	dummy = (dummy >> 1) | fix;
+	fp_div64(fix, dummy, fix, 0, dummy);
+	fix--;
+
+	for (i = 0; i < 3; i++, mantp++) {
+		if (src->mant.m32[0] == div->mant.m32[0]) {
+			fp_div64(first, rem, 0, src->mant.m32[1], div->mant.m32[0]);
+
+			fp_mul64(*mantp, dummy, first, fix);
+			*mantp += fix;
+		} else {
+			fp_div64(first, rem, src->mant.m32[0], src->mant.m32[1], div->mant.m32[0]);
+
+			fp_mul64(*mantp, dummy, first, fix);
+		}
+
+		fp_mul64(tmp.m32[0], tmp.m32[1], div->mant.m32[0], first - *mantp);
+		fp_add64(tmp.m32[0], tmp.m32[1], 0, rem);
+		tmp.m32[2] = 0;
+
+		fp_mul64(tmp64.m32[0], tmp64.m32[1], *mantp, div->mant.m32[1]);
+		fp_sub96c(tmp, 0, tmp64.m32[0], tmp64.m32[1]);
+
+		src->mant.m32[0] = tmp.m32[1];
+		src->mant.m32[1] = tmp.m32[2];
+
+		while (!fp_sub96c(tmp, 0, div->mant.m32[0], div->mant.m32[1])) {
+			src->mant.m32[0] = tmp.m32[1];
+			src->mant.m32[1] = tmp.m32[2];
+			*mantp += 1;
+		}
+	}
+}
+
+static inline void fp_putmant128(struct fp_ext *dest, union fp_mant128 *src,
+				 int shift)
+{
+	unsigned long tmp;
+
+	switch (shift) {
+	case 0:
+		dest->mant.m64 = src->m64[0];
+		dest->lowmant = src->m32[2] >> 24;
+		if (src->m32[3] || (src->m32[2] << 8))
+			dest->lowmant |= 1;
+		break;
+	case 1:
+		asm volatile ("lsl.l #1,%0"
+			: "=d" (tmp) : "0" (src->m32[2]));
+		asm volatile ("roxl.l #1,%0"
+			: "=d" (dest->mant.m32[1]) : "0" (src->m32[1]));
+		asm volatile ("roxl.l #1,%0"
+			: "=d" (dest->mant.m32[0]) : "0" (src->m32[0]));
+		dest->lowmant = tmp >> 24;
+		if (src->m32[3] || (tmp << 8))
+			dest->lowmant |= 1;
+		break;
+	case 31:
+		asm volatile ("lsr.l #1,%1; roxr.l #1,%0"
+			: "=d" (dest->mant.m32[0])
+			: "d" (src->m32[0]), "0" (src->m32[1]));
+		asm volatile ("roxr.l #1,%0"
+			: "=d" (dest->mant.m32[1]) : "0" (src->m32[2]));
+		asm volatile ("roxr.l #1,%0"
+			: "=d" (tmp) : "0" (src->m32[3]));
+		dest->lowmant = tmp >> 24;
+		if (src->m32[3] << 7)
+			dest->lowmant |= 1;
+		break;
+	case 32:
+		dest->mant.m32[0] = src->m32[1];
+		dest->mant.m32[1] = src->m32[2];
+		dest->lowmant = src->m32[3] >> 24;
+		if (src->m32[3] << 8)
+			dest->lowmant |= 1;
+		break;
+	}
+}
+
+#endif	/* MULTI_ARITH_H */
-- 
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