patch-2.2.18 linux/arch/m68k/math-emu/multi_arith.h
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- Lines: 823
- Date:
Fri Oct 13 23:36:55 2000
- Orig file:
v2.2.17/arch/m68k/math-emu/multi_arith.h
- Orig date:
Thu Jan 1 01:00:00 1970
diff -u --new-file --recursive --exclude-from /usr/src/exclude v2.2.17/arch/m68k/math-emu/multi_arith.h linux/arch/m68k/math-emu/multi_arith.h
@@ -0,0 +1,822 @@
+/* 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
+
+#if 0 /* old code... */
+
+/* Unsigned only, because we don't need signs to multiply and divide. */
+typedef unsigned int int128[4];
+
+/* Word order */
+enum {
+ MSW128,
+ NMSW128,
+ NLSW128,
+ LSW128
+};
+
+/* big-endian */
+#define LO_WORD(ll) (((unsigned int *) &ll)[1])
+#define HI_WORD(ll) (((unsigned int *) &ll)[0])
+
+/* Convenience functions to stuff various integer values into int128s */
+
+extern inline void zero128(int128 a)
+{
+ a[LSW128] = a[NLSW128] = a[NMSW128] = a[MSW128] = 0;
+}
+
+/* Human-readable word order in the arguments */
+extern inline void set128(unsigned int i3,
+ unsigned int i2,
+ unsigned int i1,
+ unsigned int i0,
+ int128 a)
+{
+ a[LSW128] = i0;
+ a[NLSW128] = i1;
+ a[NMSW128] = i2;
+ a[MSW128] = i3;
+}
+
+/* Convenience functions (for testing as well) */
+extern inline void int64_to_128(unsigned long long src,
+ int128 dest)
+{
+ dest[LSW128] = (unsigned int) src;
+ dest[NLSW128] = src >> 32;
+ dest[NMSW128] = dest[MSW128] = 0;
+}
+
+extern inline void int128_to_64(const int128 src,
+ unsigned long long *dest)
+{
+ *dest = src[LSW128] | (long long) src[NLSW128] << 32;
+}
+
+extern inline void put_i128(const int128 a)
+{
+ printk("%08x %08x %08x %08x\n", a[MSW128], a[NMSW128],
+ a[NLSW128], a[LSW128]);
+}
+
+/* Internal shifters:
+
+ Note that these are only good for 0 < count < 32.
+ */
+
+extern inline void _lsl128(unsigned int count, int128 a)
+{
+ a[MSW128] = (a[MSW128] << count) | (a[NMSW128] >> (32 - count));
+ a[NMSW128] = (a[NMSW128] << count) | (a[NLSW128] >> (32 - count));
+ a[NLSW128] = (a[NLSW128] << count) | (a[LSW128] >> (32 - count));
+ a[LSW128] <<= count;
+}
+
+extern inline void _lsr128(unsigned int count, int128 a)
+{
+ a[LSW128] = (a[LSW128] >> count) | (a[NLSW128] << (32 - count));
+ a[NLSW128] = (a[NLSW128] >> count) | (a[NMSW128] << (32 - count));
+ a[NMSW128] = (a[NMSW128] >> count) | (a[MSW128] << (32 - count));
+ a[MSW128] >>= count;
+}
+
+/* Should be faster, one would hope */
+
+extern inline void lslone128(int128 a)
+{
+ asm volatile ("lsl.l #1,%0\n"
+ "roxl.l #1,%1\n"
+ "roxl.l #1,%2\n"
+ "roxl.l #1,%3\n"
+ :
+ "=d" (a[LSW128]),
+ "=d"(a[NLSW128]),
+ "=d"(a[NMSW128]),
+ "=d"(a[MSW128])
+ :
+ "0"(a[LSW128]),
+ "1"(a[NLSW128]),
+ "2"(a[NMSW128]),
+ "3"(a[MSW128]));
+}
+
+extern inline void lsrone128(int128 a)
+{
+ asm volatile ("lsr.l #1,%0\n"
+ "roxr.l #1,%1\n"
+ "roxr.l #1,%2\n"
+ "roxr.l #1,%3\n"
+ :
+ "=d" (a[MSW128]),
+ "=d"(a[NMSW128]),
+ "=d"(a[NLSW128]),
+ "=d"(a[LSW128])
+ :
+ "0"(a[MSW128]),
+ "1"(a[NMSW128]),
+ "2"(a[NLSW128]),
+ "3"(a[LSW128]));
+}
+
+/* Generalized 128-bit shifters:
+
+ These bit-shift to a multiple of 32, then move whole longwords. */
+
+extern inline void lsl128(unsigned int count, int128 a)
+{
+ int wordcount, i;
+
+ if (count % 32)
+ _lsl128(count % 32, a);
+
+ if (0 == (wordcount = count / 32))
+ return;
+
+ /* argh, gak, endian-sensitive */
+ for (i = 0; i < 4 - wordcount; i++) {
+ a[i] = a[i + wordcount];
+ }
+ for (i = 3; i >= 4 - wordcount; --i) {
+ a[i] = 0;
+ }
+}
+
+extern inline void lsr128(unsigned int count, int128 a)
+{
+ int wordcount, i;
+
+ if (count % 32)
+ _lsr128(count % 32, a);
+
+ if (0 == (wordcount = count / 32))
+ return;
+
+ for (i = 3; i >= wordcount; --i) {
+ a[i] = a[i - wordcount];
+ }
+ for (i = 0; i < wordcount; i++) {
+ a[i] = 0;
+ }
+}
+
+extern inline int orl128(int a, int128 b)
+{
+ b[LSW128] |= a;
+}
+
+extern inline int btsthi128(const int128 a)
+{
+ return a[MSW128] & 0x80000000;
+}
+
+/* test bits (numbered from 0 = LSB) up to and including "top" */
+extern inline int bftestlo128(int top, const int128 a)
+{
+ int r = 0;
+
+ if (top > 31)
+ r |= a[LSW128];
+ if (top > 63)
+ r |= a[NLSW128];
+ if (top > 95)
+ r |= a[NMSW128];
+
+ r |= a[3 - (top / 32)] & ((1 << (top % 32 + 1)) - 1);
+
+ return (r != 0);
+}
+
+/* Aargh. We need these because GCC is broken */
+/* FIXME: do them in assembly, for goodness' sake! */
+extern inline void mask64(int pos, unsigned long long *mask)
+{
+ *mask = 0;
+
+ if (pos < 32) {
+ LO_WORD(*mask) = (1 << pos) - 1;
+ return;
+ }
+ LO_WORD(*mask) = -1;
+ HI_WORD(*mask) = (1 << (pos - 32)) - 1;
+}
+
+extern inline void bset64(int pos, unsigned long long *dest)
+{
+ /* This conditional will be optimized away. Thanks, GCC! */
+ if (pos < 32)
+ asm volatile ("bset %1,%0":"=m"
+ (LO_WORD(*dest)):"id"(pos));
+ else
+ asm volatile ("bset %1,%0":"=m"
+ (HI_WORD(*dest)):"id"(pos - 32));
+}
+
+extern inline int btst64(int pos, unsigned long long dest)
+{
+ if (pos < 32)
+ return (0 != (LO_WORD(dest) & (1 << pos)));
+ else
+ return (0 != (HI_WORD(dest) & (1 << (pos - 32))));
+}
+
+extern inline void lsl64(int count, unsigned long long *dest)
+{
+ if (count < 32) {
+ HI_WORD(*dest) = (HI_WORD(*dest) << count)
+ | (LO_WORD(*dest) >> count);
+ LO_WORD(*dest) <<= count;
+ return;
+ }
+ count -= 32;
+ HI_WORD(*dest) = LO_WORD(*dest) << count;
+ LO_WORD(*dest) = 0;
+}
+
+extern inline void lsr64(int count, unsigned long long *dest)
+{
+ if (count < 32) {
+ LO_WORD(*dest) = (LO_WORD(*dest) >> count)
+ | (HI_WORD(*dest) << (32 - count));
+ HI_WORD(*dest) >>= count;
+ return;
+ }
+ count -= 32;
+ LO_WORD(*dest) = HI_WORD(*dest) >> count;
+ HI_WORD(*dest) = 0;
+}
+#endif
+
+extern 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;
+ }
+}
+
+extern 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;
+}
+
+extern 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;
+}
+
+extern 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;
+}
+
+extern 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) \
+ : "g" (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; \
+})
+
+extern 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);
+}
+
+extern 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;
+ }
+ }
+}
+
+#if 0
+extern inline unsigned int fp_fls128(union fp_mant128 *src)
+{
+ unsigned long data;
+ unsigned int res, off;
+
+ if ((data = src->m32[0]))
+ off = 0;
+ else if ((data = src->m32[1]))
+ off = 32;
+ else if ((data = src->m32[2]))
+ off = 64;
+ else if ((data = src->m32[3]))
+ off = 96;
+ else
+ return 128;
+
+ asm ("bfffo %1{#0,#32},%0" : "=d" (res) : "dm" (data));
+ return res + off;
+}
+
+extern inline void fp_shiftmant128(union fp_mant128 *src, int shift)
+{
+ unsigned long sticky;
+
+ switch (shift) {
+ case 0:
+ return;
+ case 1:
+ asm volatile ("lsl.l #1,%0"
+ : "=d" (src->m32[3]) : "0" (src->m32[3]));
+ asm volatile ("roxl.l #1,%0"
+ : "=d" (src->m32[2]) : "0" (src->m32[2]));
+ asm volatile ("roxl.l #1,%0"
+ : "=d" (src->m32[1]) : "0" (src->m32[1]));
+ asm volatile ("roxl.l #1,%0"
+ : "=d" (src->m32[0]) : "0" (src->m32[0]));
+ return;
+ case 2 ... 31:
+ src->m32[0] = (src->m32[0] << shift) | (src->m32[1] >> (32 - shift));
+ src->m32[1] = (src->m32[1] << shift) | (src->m32[2] >> (32 - shift));
+ src->m32[2] = (src->m32[2] << shift) | (src->m32[3] >> (32 - shift));
+ src->m32[3] = (src->m32[3] << shift);
+ return;
+ case 32 ... 63:
+ shift -= 32;
+ src->m32[0] = (src->m32[1] << shift) | (src->m32[2] >> (32 - shift));
+ src->m32[1] = (src->m32[2] << shift) | (src->m32[3] >> (32 - shift));
+ src->m32[2] = (src->m32[3] << shift);
+ src->m32[3] = 0;
+ return;
+ case 64 ... 95:
+ shift -= 64;
+ src->m32[0] = (src->m32[2] << shift) | (src->m32[3] >> (32 - shift));
+ src->m32[1] = (src->m32[3] << shift);
+ src->m32[2] = src->m32[3] = 0;
+ return;
+ case 96 ... 127:
+ shift -= 96;
+ src->m32[0] = (src->m32[3] << shift);
+ src->m32[1] = src->m32[2] = src->m32[3] = 0;
+ return;
+ case -31 ... -1:
+ shift = -shift;
+ sticky = 0;
+ if (src->m32[3] << (32 - shift))
+ sticky = 1;
+ src->m32[3] = (src->m32[3] >> shift) | (src->m32[2] << (32 - shift)) | sticky;
+ src->m32[2] = (src->m32[2] >> shift) | (src->m32[1] << (32 - shift));
+ src->m32[1] = (src->m32[1] >> shift) | (src->m32[0] << (32 - shift));
+ src->m32[0] = (src->m32[0] >> shift);
+ return;
+ case -63 ... -32:
+ shift = -shift - 32;
+ sticky = 0;
+ if ((src->m32[2] << (32 - shift)) || src->m32[3])
+ sticky = 1;
+ src->m32[3] = (src->m32[2] >> shift) | (src->m32[1] << (32 - shift)) | sticky;
+ src->m32[2] = (src->m32[1] >> shift) | (src->m32[0] << (32 - shift));
+ src->m32[1] = (src->m32[0] >> shift);
+ src->m32[0] = 0;
+ return;
+ case -95 ... -64:
+ shift = -shift - 64;
+ sticky = 0;
+ if ((src->m32[1] << (32 - shift)) || src->m32[2] || src->m32[3])
+ sticky = 1;
+ src->m32[3] = (src->m32[1] >> shift) | (src->m32[0] << (32 - shift)) | sticky;
+ src->m32[2] = (src->m32[0] >> shift);
+ src->m32[1] = src->m32[0] = 0;
+ return;
+ case -127 ... -96:
+ shift = -shift - 96;
+ sticky = 0;
+ if ((src->m32[0] << (32 - shift)) || src->m32[1] || src->m32[2] || src->m32[3])
+ sticky = 1;
+ src->m32[3] = (src->m32[0] >> shift) | sticky;
+ src->m32[2] = src->m32[1] = src->m32[0] = 0;
+ return;
+ }
+
+ if (shift < 0 && (src->m32[0] || src->m32[1] || src->m32[2] || src->m32[3]))
+ src->m32[3] = 1;
+ else
+ src->m32[3] = 0;
+ src->m32[2] = 0;
+ src->m32[1] = 0;
+ src->m32[0] = 0;
+}
+#endif
+
+extern 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;
+ }
+}
+
+#if 0 /* old code... */
+extern inline int fls(unsigned int a)
+{
+ int r;
+
+ asm volatile ("bfffo %1{#0,#32},%0"
+ : "=d" (r) : "md" (a));
+ return r;
+}
+
+/* fls = "find last set" (cf. ffs(3)) */
+extern inline int fls128(const int128 a)
+{
+ if (a[MSW128])
+ return fls(a[MSW128]);
+ if (a[NMSW128])
+ return fls(a[NMSW128]) + 32;
+ /* XXX: it probably never gets beyond this point in actual
+ use, but that's indicative of a more general problem in the
+ algorithm (i.e. as per the actual 68881 implementation, we
+ really only need at most 67 bits of precision [plus
+ overflow]) so I'm not going to fix it. */
+ if (a[NLSW128])
+ return fls(a[NLSW128]) + 64;
+ if (a[LSW128])
+ return fls(a[LSW128]) + 96;
+ else
+ return -1;
+}
+
+extern inline int zerop128(const int128 a)
+{
+ return !(a[LSW128] | a[NLSW128] | a[NMSW128] | a[MSW128]);
+}
+
+extern inline int nonzerop128(const int128 a)
+{
+ return (a[LSW128] | a[NLSW128] | a[NMSW128] | a[MSW128]);
+}
+
+/* Addition and subtraction */
+/* Do these in "pure" assembly, because "extended" asm is unmanageable
+ here */
+extern inline void add128(const int128 a, int128 b)
+{
+ /* rotating carry flags */
+ unsigned int carry[2];
+
+ carry[0] = a[LSW128] > (0xffffffff - b[LSW128]);
+ b[LSW128] += a[LSW128];
+
+ carry[1] = a[NLSW128] > (0xffffffff - b[NLSW128] - carry[0]);
+ b[NLSW128] = a[NLSW128] + b[NLSW128] + carry[0];
+
+ carry[0] = a[NMSW128] > (0xffffffff - b[NMSW128] - carry[1]);
+ b[NMSW128] = a[NMSW128] + b[NMSW128] + carry[1];
+
+ b[MSW128] = a[MSW128] + b[MSW128] + carry[0];
+}
+
+/* Note: assembler semantics: "b -= a" */
+extern inline void sub128(const int128 a, int128 b)
+{
+ /* rotating borrow flags */
+ unsigned int borrow[2];
+
+ borrow[0] = b[LSW128] < a[LSW128];
+ b[LSW128] -= a[LSW128];
+
+ borrow[1] = b[NLSW128] < a[NLSW128] + borrow[0];
+ b[NLSW128] = b[NLSW128] - a[NLSW128] - borrow[0];
+
+ borrow[0] = b[NMSW128] < a[NMSW128] + borrow[1];
+ b[NMSW128] = b[NMSW128] - a[NMSW128] - borrow[1];
+
+ b[MSW128] = b[MSW128] - a[MSW128] - borrow[0];
+}
+
+/* Poor man's 64-bit expanding multiply */
+extern inline void mul64(unsigned long long a,
+ unsigned long long b,
+ int128 c)
+{
+ unsigned long long acc;
+ int128 acc128;
+
+ zero128(acc128);
+ zero128(c);
+
+ /* first the low words */
+ if (LO_WORD(a) && LO_WORD(b)) {
+ acc = (long long) LO_WORD(a) * LO_WORD(b);
+ c[NLSW128] = HI_WORD(acc);
+ c[LSW128] = LO_WORD(acc);
+ }
+ /* Next the high words */
+ if (HI_WORD(a) && HI_WORD(b)) {
+ acc = (long long) HI_WORD(a) * HI_WORD(b);
+ c[MSW128] = HI_WORD(acc);
+ c[NMSW128] = LO_WORD(acc);
+ }
+ /* The middle words */
+ if (LO_WORD(a) && HI_WORD(b)) {
+ acc = (long long) LO_WORD(a) * HI_WORD(b);
+ acc128[NMSW128] = HI_WORD(acc);
+ acc128[NLSW128] = LO_WORD(acc);
+ add128(acc128, c);
+ }
+ /* The first and last words */
+ if (HI_WORD(a) && LO_WORD(b)) {
+ acc = (long long) HI_WORD(a) * LO_WORD(b);
+ acc128[NMSW128] = HI_WORD(acc);
+ acc128[NLSW128] = LO_WORD(acc);
+ add128(acc128, c);
+ }
+}
+
+/* Note: unsigned */
+extern inline int cmp128(int128 a, int128 b)
+{
+ if (a[MSW128] < b[MSW128])
+ return -1;
+ if (a[MSW128] > b[MSW128])
+ return 1;
+ if (a[NMSW128] < b[NMSW128])
+ return -1;
+ if (a[NMSW128] > b[NMSW128])
+ return 1;
+ if (a[NLSW128] < b[NLSW128])
+ return -1;
+ if (a[NLSW128] > b[NLSW128])
+ return 1;
+
+ return (signed) a[LSW128] - b[LSW128];
+}
+
+inline void div128(int128 a, int128 b, int128 c)
+{
+ int128 mask;
+
+ /* Algorithm:
+
+ Shift the divisor until it's at least as big as the
+ dividend, keeping track of the position to which we've
+ shifted it, i.e. the power of 2 which we've multiplied it
+ by.
+
+ Then, for this power of 2 (the mask), and every one smaller
+ than it, subtract the mask from the dividend and add it to
+ the quotient until the dividend is smaller than the raised
+ divisor. At this point, divide the dividend and the mask
+ by 2 (i.e. shift one place to the right). Lather, rinse,
+ and repeat, until there are no more powers of 2 left. */
+
+ /* FIXME: needless to say, there's room for improvement here too. */
+
+ /* Shift up */
+ /* XXX: since it just has to be "at least as big", we can
+ probably eliminate this horribly wasteful loop. I will
+ have to prove this first, though */
+ set128(0, 0, 0, 1, mask);
+ while (cmp128(b, a) < 0 && !btsthi128(b)) {
+ lslone128(b);
+ lslone128(mask);
+ }
+
+ /* Shift down */
+ zero128(c);
+ do {
+ if (cmp128(a, b) >= 0) {
+ sub128(b, a);
+ add128(mask, c);
+ }
+ lsrone128(mask);
+ lsrone128(b);
+ } while (nonzerop128(mask));
+
+ /* The remainder is in a... */
+}
+#endif
+
+#endif /* MULTI_ARITH_H */
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)