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/***********************************************************************/
/* */
/* OCaml */
/* */
/* Xavier Leroy, projet Cristal, INRIA Rocquencourt */
/* */
/* Copyright 2003 Institut National de Recherche en Informatique et */
/* en Automatique. All rights reserved. This file is distributed */
/* under the terms of the GNU Library General Public License, with */
/* the special exception on linking described in file ../../LICENSE. */
/* */
/***********************************************************************/
/* $Id$ */
/* Code specific to the Intel IA32 (x86) architecture. */
#define BngAdd2(res,carryout,arg1,arg2) \
asm("xorl %1, %1 \n\t" \
"addl %3, %0 \n\t" \
"setc %b1" \
: "=r" (res), "=&q" (carryout) \
: "0" (arg1), "rm" (arg2))
#define BngSub2(res,carryout,arg1,arg2) \
asm("xorl %1, %1 \n\t" \
"subl %3, %0 \n\t" \
"setc %b1" \
: "=r" (res), "=&q" (carryout) \
: "0" (arg1), "rm" (arg2))
#define BngMult(resh,resl,arg1,arg2) \
asm("mull %3" \
: "=a" (resl), "=d" (resh) \
: "a" (arg1), "r" (arg2))
#define BngDiv(quo,rem,nh,nl,d) \
asm("divl %4" \
: "=a" (quo), "=d" (rem) \
: "a" (nl), "d" (nh), "r" (d))
/* Reimplementation in asm of some of the bng operations. */
static bngcarry bng_ia32_add
(bng a/*[alen]*/, bngsize alen,
bng b/*[blen]*/, bngsize blen,
bngcarry carry)
{
bngdigit tmp;
alen -= blen;
if (blen > 0) {
asm("negb %b3 \n\t"
"1: \n\t"
"movl (%0), %4 \n\t"
"adcl (%1), %4 \n\t"
"movl %4, (%0) \n\t"
"leal 4(%0), %0 \n\t"
"leal 4(%1), %1 \n\t"
"decl %2 \n\t"
"jnz 1b \n\t"
"setc %b3"
: "+&r" (a), "+&r" (b), "+&r" (blen), "+&q" (carry), "=&r" (tmp));
}
if (carry == 0 || alen == 0) return carry;
do {
if (++(*a) != 0) return 0;
a++;
} while (--alen);
return 1;
}
static bngcarry bng_ia32_sub
(bng a/*[alen]*/, bngsize alen,
bng b/*[blen]*/, bngsize blen,
bngcarry carry)
{
bngdigit tmp;
alen -= blen;
if (blen > 0) {
asm("negb %b3 \n\t"
"1: \n\t"
"movl (%0), %4 \n\t"
"sbbl (%1), %4 \n\t"
"movl %4, (%0) \n\t"
"leal 4(%0), %0 \n\t"
"leal 4(%1), %1 \n\t"
"decl %2 \n\t"
"jnz 1b \n\t"
"setc %b3"
: "+&r" (a), "+&r" (b), "+&r" (blen), "+&q" (carry), "=&r" (tmp));
}
if (carry == 0 || alen == 0) return carry;
do {
if ((*a)-- != 0) return 0;
a++;
} while (--alen);
return 1;
}
static bngdigit bng_ia32_mult_add_digit
(bng a/*[alen]*/, bngsize alen,
bng b/*[blen]*/, bngsize blen,
bngdigit d)
{
bngdigit out;
bngcarry carry;
alen -= blen;
out = 0;
if (blen > 0) {
asm("1: \n\t"
"movl (%1), %%eax \n\t"
"mull %4\n\t" /* edx:eax = d * next digit of b */
"addl (%0), %%eax \n\t" /* add next digit of a to eax */
"adcl $0, %%edx \n\t" /* accumulate carry in edx */
"addl %3, %%eax \n\t" /* add out to eax */
"adcl $0, %%edx \n\t" /* accumulate carry in edx */
"movl %%eax, (%0) \n\t" /* eax is next digit of result */
"movl %%edx, %3 \n\t" /* edx is next out */
"leal 4(%0), %0 \n\t"
"leal 4(%1), %1 \n\t"
"decl %2 \n\t"
"jnz 1b"
: "+&r" (a), "+&r" (b), "+&r" (blen), "=m" (out)
: "m" (d)
: "eax", "edx");
}
if (alen == 0) return out;
/* current digit of a += out */
BngAdd2(*a, carry, *a, out);
a++;
alen--;
/* Propagate carry */
if (carry == 0 || alen == 0) return carry;
do {
if (++(*a) != 0) return 0;
a++;
} while (--alen);
return 1;
}
static bngdigit bng_ia32_mult_sub_digit
(bng a/*[alen]*/, bngsize alen,
bng b/*[blen]*/, bngsize blen,
bngdigit d)
{
bngdigit out, tmp;
bngcarry carry;
alen -= blen;
out = 0;
if (blen > 0) {
asm("1: \n\t"
"movl (%1), %%eax \n\t"
"movl (%0), %4 \n\t"
"mull %5\n\t" /* edx:eax = d * next digit of b */
"subl %%eax, %4 \n\t" /* subtract eax from next digit of a */
"adcl $0, %%edx \n\t" /* accumulate carry in edx */
"subl %3, %4 \n\t" /* subtract out */
"adcl $0, %%edx \n\t" /* accumulate carry in edx */
"movl %4, (%0) \n\t" /* store next digit of result */
"movl %%edx, %3 \n\t" /* edx is next out */
"leal 4(%0), %0 \n\t"
"leal 4(%1), %1 \n\t"
"decl %2 \n\t"
"jnz 1b"
: "+&r" (a), "+&r" (b), "=m" (blen), "=m" (out), "=&r" (tmp)
: "m" (d)
: "eax", "edx");
}
if (alen == 0) return out;
/* current digit of a -= out */
BngSub2(*a, carry, *a, out);
a++;
alen--;
/* Propagate carry */
if (carry == 0 || alen == 0) return carry;
do {
if ((*a)-- != 0) return 0;
a++;
} while (--alen);
return 1;
}
/* This is another asm implementation of some of the bng operations,
using SSE2 operations to provide 64-bit arithmetic.
This is faster than the plain IA32 code above on the Pentium 4.
(Arithmetic operations with carry are slow on the Pentium 4). */
#if BNG_ASM_LEVEL >= 2
static bngcarry bng_ia32sse2_add
(bng a/*[alen]*/, bngsize alen,
bng b/*[blen]*/, bngsize blen,
bngcarry carry)
{
alen -= blen;
if (blen > 0) {
asm("movd %3, %%mm0 \n\t" /* MM0 is carry */
"1: \n\t"
"movd (%0), %%mm1 \n\t" /* MM1 is next digit of a */
"movd (%1), %%mm2 \n\t" /* MM2 is next digit of b */
"paddq %%mm1, %%mm0 \n\t" /* Add carry (64 bits) */
"paddq %%mm2, %%mm0 \n\t" /* Add digits (64 bits) */
"movd %%mm0, (%0) \n\t" /* Store low 32 bits of result */
"psrlq $32, %%mm0 \n\t" /* Next carry is top 32 bits of results */
"addl $4, %0\n\t"
"addl $4, %1\n\t"
"subl $1, %2\n\t"
"jne 1b \n\t"
"movd %%mm0, %3 \n\t"
"emms"
: "+&r" (a), "+&r" (b), "+&r" (blen), "+&rm" (carry));
}
if (carry == 0 || alen == 0) return carry;
do {
if (++(*a) != 0) return 0;
a++;
} while (--alen);
return 1;
}
static bngcarry bng_ia32sse2_sub
(bng a/*[alen]*/, bngsize alen,
bng b/*[blen]*/, bngsize blen,
bngcarry carry)
{
alen -= blen;
if (blen > 0) {
asm("movd %3, %%mm0 \n\t" /* MM0 is carry */
"1: \n\t"
"movd (%0), %%mm1 \n\t" /* MM1 is next digit of a */
"movd (%1), %%mm2 \n\t" /* MM2 is next digit of b */
"psubq %%mm0, %%mm1 \n\t" /* Subtract carry (64 bits) */
"psubq %%mm2, %%mm1 \n\t" /* Subtract digits (64 bits) */
"movd %%mm1, (%0) \n\t" /* Store low 32 bits of result */
"psrlq $63, %%mm1 \n\t" /* Next carry is sign bit of result */
"movq %%mm1, %%mm0 \n\t"
"addl $4, %0\n\t"
"addl $4, %1\n\t"
"subl $1, %2\n\t"
"jne 1b \n\t"
"movd %%mm0, %3 \n\t"
"emms"
: "+&r" (a), "+&r" (b), "+&r" (blen), "+&rm" (carry));
}
if (carry == 0 || alen == 0) return carry;
do {
if ((*a)-- != 0) return 0;
a++;
} while (--alen);
return 1;
}
static bngdigit bng_ia32sse2_mult_add_digit
(bng a/*[alen]*/, bngsize alen,
bng b/*[blen]*/, bngsize blen,
bngdigit d)
{
bngdigit out;
bngcarry carry;
alen -= blen;
out = 0;
if (blen > 0) {
asm("pxor %%mm0, %%mm0 \n\t" /* MM0 is carry */
"movd %4, %%mm7 \n\t" /* MM7 is digit d */
"1: \n\t"
"movd (%0), %%mm1 \n\t" /* MM1 is next digit of a */
"movd (%1), %%mm2 \n\t" /* MM2 is next digit of b */
"pmuludq %%mm7, %%mm2 \n\t" /* MM2 = d * digit of b */
"paddq %%mm1, %%mm0 \n\t" /* Add product and carry ... */
"paddq %%mm2, %%mm0 \n\t" /* ... and digit of a */
"movd %%mm0, (%0) \n\t" /* Store low 32 bits of result */
"psrlq $32, %%mm0 \n\t" /* Next carry is high 32 bits result */
"addl $4, %0\n\t"
"addl $4, %1\n\t"
"subl $1, %2\n\t"
"jne 1b \n\t"
"movd %%mm0, %3 \n\t"
"emms"
: "+&r" (a), "+&r" (b), "+&r" (blen), "=&rm" (out)
: "m" (d));
}
if (alen == 0) return out;
/* current digit of a += out */
BngAdd2(*a, carry, *a, out);
a++;
alen--;
/* Propagate carry */
if (carry == 0 || alen == 0) return carry;
do {
if (++(*a) != 0) return 0;
a++;
} while (--alen);
return 1;
}
static bngdigit bng_ia32sse2_mult_sub_digit
(bng a/*[alen]*/, bngsize alen,
bng b/*[blen]*/, bngsize blen,
bngdigit d)
{
static unsigned long long bias1 = 0xFFFFFFFF00000000ULL - 0xFFFFFFFFULL;
static unsigned long bias2 = 0xFFFFFFFFUL;
bngdigit out;
bngcarry carry;
alen -= blen;
out = 0;
if (blen > 0) {
/* Carry C is represented by ENC(C) = 0xFFFFFFFF - C (one's complement) */
asm("movd %6, %%mm0 \n\t" /* MM0 is carry (initially 0xFFFFFFFF) */
"movq %5, %%mm6 \n\t" /* MM6 is magic constant bias1 */
"movd %4, %%mm7 \n\t" /* MM7 is digit d */
"1: \n\t"
"movd (%0), %%mm1 \n\t" /* MM1 is next digit of a */
"movd (%1), %%mm2 \n\t" /* MM2 is next digit of b */
"paddq %%mm6, %%mm1 \n\t" /* bias digit of a */
"pmuludq %%mm7, %%mm2 \n\t" /* MM2 = d * digit of b */
/* Compute
digit of a + ENC(carry) + 0xFFFFFFFF00000000 - 0xFFFFFFFF - product
= digit of a - carry + 0xFFFFFFFF00000000 - product
= digit of a - carry - productlow + (ENC(nextcarry) << 32) */
"psubq %%mm2, %%mm1 \n\t"
"paddq %%mm1, %%mm0 \n\t"
"movd %%mm0, (%0) \n\t" /* Store low 32 bits of result */
"psrlq $32, %%mm0 \n\t" /* Next carry is 32 high bits of result */
"addl $4, %0\n\t"
"addl $4, %1\n\t"
"subl $1, %2\n\t"
"jne 1b \n\t"
"movd %%mm0, %3 \n\t"
"emms"
: "+&r" (a), "+&r" (b), "+&r" (blen), "=&rm" (out)
: "m" (d), "m" (bias1), "m" (bias2));
out = ~out; /* Undo encoding on out digit */
}
if (alen == 0) return out;
/* current digit of a -= out */
BngSub2(*a, carry, *a, out);
a++;
alen--;
/* Propagate carry */
if (carry == 0 || alen == 0) return carry;
do {
if ((*a)-- != 0) return 0;
a++;
} while (--alen);
return 1;
}
/* Detect whether SSE2 instructions are supported */
static int bng_ia32_sse2_supported(void)
{
unsigned int flags, newflags, max_id, capabilities;
#define EFLAG_CPUID 0x00200000
#define CPUID_IDENTIFY 0
#define CPUID_CAPABILITIES 1
#define SSE2_CAPABILITY 26
/* Check if processor has CPUID instruction */
asm("pushfl \n\t"
"popl %0"
: "=r" (flags) : );
newflags = flags ^ EFLAG_CPUID; /* CPUID detection flag */
asm("pushfl \n\t"
"pushl %1 \n\t"
"popfl \n\t"
"pushfl \n\t"
"popl %0 \n\t"
"popfl"
: "=r" (flags) : "r" (newflags));
/* If CPUID detection flag cannot be changed, CPUID instruction is not
available */
if ((flags & EFLAG_CPUID) != (newflags & EFLAG_CPUID)) return 0;
/* See if SSE2 extensions are supported */
asm("pushl %%ebx \n\t" /* need to preserve %ebx for PIC */
"cpuid \n\t"
"popl %%ebx"
: "=a" (max_id) : "a" (CPUID_IDENTIFY): "ecx", "edx");
if (max_id < 1) return 0;
asm("pushl %%ebx \n\t"
"cpuid \n\t"
"popl %%ebx"
: "=d" (capabilities) : "a" (CPUID_CAPABILITIES) : "ecx");
return capabilities & (1 << SSE2_CAPABILITY);
}
#endif
static void bng_ia32_setup_ops(void)
{
#if BNG_ASM_LEVEL >= 2
if (bng_ia32_sse2_supported()) {
bng_ops.add = bng_ia32sse2_add;
bng_ops.sub = bng_ia32sse2_sub;
bng_ops.mult_add_digit = bng_ia32sse2_mult_add_digit;
bng_ops.mult_sub_digit = bng_ia32sse2_mult_sub_digit;
return;
}
#endif
bng_ops.add = bng_ia32_add;
bng_ops.sub = bng_ia32_sub;
bng_ops.mult_add_digit = bng_ia32_mult_add_digit;
bng_ops.mult_sub_digit = bng_ia32_mult_sub_digit;
}
#define BNG_SETUP_OPS bng_ia32_setup_ops()
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