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qemu/target/i386/int_helper.c
Richard Henderson 369fd5ca66 target/i386: Implement CPUID_EXT_RDRAND 
We now have an interface for guest visible random numbers.

Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-05-22 12:38:54 -04:00

494 lines
12 KiB
C
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/*
* x86 integer helpers
*
* Copyright (c) 2003 Fabrice Bellard
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "cpu.h"
#include "exec/exec-all.h"
#include "qemu/host-utils.h"
#include "exec/helper-proto.h"
#include "qapi/error.h"
#include "qemu/guest-random.h"
//#define DEBUG_MULDIV
/* modulo 9 table */
static const uint8_t rclb_table[32] = {
0, 1, 2, 3, 4, 5, 6, 7,
8, 0, 1, 2, 3, 4, 5, 6,
7, 8, 0, 1, 2, 3, 4, 5,
6, 7, 8, 0, 1, 2, 3, 4,
};
/* modulo 17 table */
static const uint8_t rclw_table[32] = {
0, 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13, 14, 15,
16, 0, 1, 2, 3, 4, 5, 6,
7, 8, 9, 10, 11, 12, 13, 14,
};
/* division, flags are undefined */
void helper_divb_AL(CPUX86State *env, target_ulong t0)
{
unsigned int num, den, q, r;
num = (env->regs[R_EAX] & 0xffff);
den = (t0 & 0xff);
if (den == 0) {
raise_exception_ra(env, EXCP00_DIVZ, GETPC());
}
q = (num / den);
if (q > 0xff) {
raise_exception_ra(env, EXCP00_DIVZ, GETPC());
}
q &= 0xff;
r = (num % den) & 0xff;
env->regs[R_EAX] = (env->regs[R_EAX] & ~0xffff) | (r << 8) | q;
}
void helper_idivb_AL(CPUX86State *env, target_ulong t0)
{
int num, den, q, r;
num = (int16_t)env->regs[R_EAX];
den = (int8_t)t0;
if (den == 0) {
raise_exception_ra(env, EXCP00_DIVZ, GETPC());
}
q = (num / den);
if (q != (int8_t)q) {
raise_exception_ra(env, EXCP00_DIVZ, GETPC());
}
q &= 0xff;
r = (num % den) & 0xff;
env->regs[R_EAX] = (env->regs[R_EAX] & ~0xffff) | (r << 8) | q;
}
void helper_divw_AX(CPUX86State *env, target_ulong t0)
{
unsigned int num, den, q, r;
num = (env->regs[R_EAX] & 0xffff) | ((env->regs[R_EDX] & 0xffff) << 16);
den = (t0 & 0xffff);
if (den == 0) {
raise_exception_ra(env, EXCP00_DIVZ, GETPC());
}
q = (num / den);
if (q > 0xffff) {
raise_exception_ra(env, EXCP00_DIVZ, GETPC());
}
q &= 0xffff;
r = (num % den) & 0xffff;
env->regs[R_EAX] = (env->regs[R_EAX] & ~0xffff) | q;
env->regs[R_EDX] = (env->regs[R_EDX] & ~0xffff) | r;
}
void helper_idivw_AX(CPUX86State *env, target_ulong t0)
{
int num, den, q, r;
num = (env->regs[R_EAX] & 0xffff) | ((env->regs[R_EDX] & 0xffff) << 16);
den = (int16_t)t0;
if (den == 0) {
raise_exception_ra(env, EXCP00_DIVZ, GETPC());
}
q = (num / den);
if (q != (int16_t)q) {
raise_exception_ra(env, EXCP00_DIVZ, GETPC());
}
q &= 0xffff;
r = (num % den) & 0xffff;
env->regs[R_EAX] = (env->regs[R_EAX] & ~0xffff) | q;
env->regs[R_EDX] = (env->regs[R_EDX] & ~0xffff) | r;
}
void helper_divl_EAX(CPUX86State *env, target_ulong t0)
{
unsigned int den, r;
uint64_t num, q;
num = ((uint32_t)env->regs[R_EAX]) | ((uint64_t)((uint32_t)env->regs[R_EDX]) << 32);
den = t0;
if (den == 0) {
raise_exception_ra(env, EXCP00_DIVZ, GETPC());
}
q = (num / den);
r = (num % den);
if (q > 0xffffffff) {
raise_exception_ra(env, EXCP00_DIVZ, GETPC());
}
env->regs[R_EAX] = (uint32_t)q;
env->regs[R_EDX] = (uint32_t)r;
}
void helper_idivl_EAX(CPUX86State *env, target_ulong t0)
{
int den, r;
int64_t num, q;
num = ((uint32_t)env->regs[R_EAX]) | ((uint64_t)((uint32_t)env->regs[R_EDX]) << 32);
den = t0;
if (den == 0) {
raise_exception_ra(env, EXCP00_DIVZ, GETPC());
}
q = (num / den);
r = (num % den);
if (q != (int32_t)q) {
raise_exception_ra(env, EXCP00_DIVZ, GETPC());
}
env->regs[R_EAX] = (uint32_t)q;
env->regs[R_EDX] = (uint32_t)r;
}
/* bcd */
/* XXX: exception */
void helper_aam(CPUX86State *env, int base)
{
int al, ah;
al = env->regs[R_EAX] & 0xff;
ah = al / base;
al = al % base;
env->regs[R_EAX] = (env->regs[R_EAX] & ~0xffff) | al | (ah << 8);
CC_DST = al;
}
void helper_aad(CPUX86State *env, int base)
{
int al, ah;
al = env->regs[R_EAX] & 0xff;
ah = (env->regs[R_EAX] >> 8) & 0xff;
al = ((ah * base) + al) & 0xff;
env->regs[R_EAX] = (env->regs[R_EAX] & ~0xffff) | al;
CC_DST = al;
}
void helper_aaa(CPUX86State *env)
{
int icarry;
int al, ah, af;
int eflags;
eflags = cpu_cc_compute_all(env, CC_OP);
af = eflags & CC_A;
al = env->regs[R_EAX] & 0xff;
ah = (env->regs[R_EAX] >> 8) & 0xff;
icarry = (al > 0xf9);
if (((al & 0x0f) > 9) || af) {
al = (al + 6) & 0x0f;
ah = (ah + 1 + icarry) & 0xff;
eflags |= CC_C | CC_A;
} else {
eflags &= ~(CC_C | CC_A);
al &= 0x0f;
}
env->regs[R_EAX] = (env->regs[R_EAX] & ~0xffff) | al | (ah << 8);
CC_SRC = eflags;
}
void helper_aas(CPUX86State *env)
{
int icarry;
int al, ah, af;
int eflags;
eflags = cpu_cc_compute_all(env, CC_OP);
af = eflags & CC_A;
al = env->regs[R_EAX] & 0xff;
ah = (env->regs[R_EAX] >> 8) & 0xff;
icarry = (al < 6);
if (((al & 0x0f) > 9) || af) {
al = (al - 6) & 0x0f;
ah = (ah - 1 - icarry) & 0xff;
eflags |= CC_C | CC_A;
} else {
eflags &= ~(CC_C | CC_A);
al &= 0x0f;
}
env->regs[R_EAX] = (env->regs[R_EAX] & ~0xffff) | al | (ah << 8);
CC_SRC = eflags;
}
void helper_daa(CPUX86State *env)
{
int old_al, al, af, cf;
int eflags;
eflags = cpu_cc_compute_all(env, CC_OP);
cf = eflags & CC_C;
af = eflags & CC_A;
old_al = al = env->regs[R_EAX] & 0xff;
eflags = 0;
if (((al & 0x0f) > 9) || af) {
al = (al + 6) & 0xff;
eflags |= CC_A;
}
if ((old_al > 0x99) || cf) {
al = (al + 0x60) & 0xff;
eflags |= CC_C;
}
env->regs[R_EAX] = (env->regs[R_EAX] & ~0xff) | al;
/* well, speed is not an issue here, so we compute the flags by hand */
eflags |= (al == 0) << 6; /* zf */
eflags |= parity_table[al]; /* pf */
eflags |= (al & 0x80); /* sf */
CC_SRC = eflags;
}
void helper_das(CPUX86State *env)
{
int al, al1, af, cf;
int eflags;
eflags = cpu_cc_compute_all(env, CC_OP);
cf = eflags & CC_C;
af = eflags & CC_A;
al = env->regs[R_EAX] & 0xff;
eflags = 0;
al1 = al;
if (((al & 0x0f) > 9) || af) {
eflags |= CC_A;
if (al < 6 || cf) {
eflags |= CC_C;
}
al = (al - 6) & 0xff;
}
if ((al1 > 0x99) || cf) {
al = (al - 0x60) & 0xff;
eflags |= CC_C;
}
env->regs[R_EAX] = (env->regs[R_EAX] & ~0xff) | al;
/* well, speed is not an issue here, so we compute the flags by hand */
eflags |= (al == 0) << 6; /* zf */
eflags |= parity_table[al]; /* pf */
eflags |= (al & 0x80); /* sf */
CC_SRC = eflags;
}
#ifdef TARGET_X86_64
static void add128(uint64_t *plow, uint64_t *phigh, uint64_t a, uint64_t b)
{
*plow += a;
/* carry test */
if (*plow < a) {
(*phigh)++;
}
*phigh += b;
}
static void neg128(uint64_t *plow, uint64_t *phigh)
{
*plow = ~*plow;
*phigh = ~*phigh;
add128(plow, phigh, 1, 0);
}
/* return TRUE if overflow */
static int div64(uint64_t *plow, uint64_t *phigh, uint64_t b)
{
uint64_t q, r, a1, a0;
int i, qb, ab;
a0 = *plow;
a1 = *phigh;
if (a1 == 0) {
q = a0 / b;
r = a0 % b;
*plow = q;
*phigh = r;
} else {
if (a1 >= b) {
return 1;
}
/* XXX: use a better algorithm */
for (i = 0; i < 64; i++) {
ab = a1 >> 63;
a1 = (a1 << 1) | (a0 >> 63);
if (ab || a1 >= b) {
a1 -= b;
qb = 1;
} else {
qb = 0;
}
a0 = (a0 << 1) | qb;
}
#if defined(DEBUG_MULDIV)
printf("div: 0x%016" PRIx64 "%016" PRIx64 " / 0x%016" PRIx64
": q=0x%016" PRIx64 " r=0x%016" PRIx64 "\n",
*phigh, *plow, b, a0, a1);
#endif
*plow = a0;
*phigh = a1;
}
return 0;
}
/* return TRUE if overflow */
static int idiv64(uint64_t *plow, uint64_t *phigh, int64_t b)
{
int sa, sb;
sa = ((int64_t)*phigh < 0);
if (sa) {
neg128(plow, phigh);
}
sb = (b < 0);
if (sb) {
b = -b;
}
if (div64(plow, phigh, b) != 0) {
return 1;
}
if (sa ^ sb) {
if (*plow > (1ULL << 63)) {
return 1;
}
*plow = -*plow;
} else {
if (*plow >= (1ULL << 63)) {
return 1;
}
}
if (sa) {
*phigh = -*phigh;
}
return 0;
}
void helper_divq_EAX(CPUX86State *env, target_ulong t0)
{
uint64_t r0, r1;
if (t0 == 0) {
raise_exception_ra(env, EXCP00_DIVZ, GETPC());
}
r0 = env->regs[R_EAX];
r1 = env->regs[R_EDX];
if (div64(&r0, &r1, t0)) {
raise_exception_ra(env, EXCP00_DIVZ, GETPC());
}
env->regs[R_EAX] = r0;
env->regs[R_EDX] = r1;
}
void helper_idivq_EAX(CPUX86State *env, target_ulong t0)
{
uint64_t r0, r1;
if (t0 == 0) {
raise_exception_ra(env, EXCP00_DIVZ, GETPC());
}
r0 = env->regs[R_EAX];
r1 = env->regs[R_EDX];
if (idiv64(&r0, &r1, t0)) {
raise_exception_ra(env, EXCP00_DIVZ, GETPC());
}
env->regs[R_EAX] = r0;
env->regs[R_EDX] = r1;
}
#endif
#if TARGET_LONG_BITS == 32
# define ctztl ctz32
# define clztl clz32
#else
# define ctztl ctz64
# define clztl clz64
#endif
target_ulong helper_pdep(target_ulong src, target_ulong mask)
{
target_ulong dest = 0;
int i, o;
for (i = 0; mask != 0; i++) {
o = ctztl(mask);
mask &= mask - 1;
dest |= ((src >> i) & 1) << o;
}
return dest;
}
target_ulong helper_pext(target_ulong src, target_ulong mask)
{
target_ulong dest = 0;
int i, o;
for (o = 0; mask != 0; o++) {
i = ctztl(mask);
mask &= mask - 1;
dest |= ((src >> i) & 1) << o;
}
return dest;
}
#define SHIFT 0
#include "shift_helper_template.h"
#undef SHIFT
#define SHIFT 1
#include "shift_helper_template.h"
#undef SHIFT
#define SHIFT 2
#include "shift_helper_template.h"
#undef SHIFT
#ifdef TARGET_X86_64
#define SHIFT 3
#include "shift_helper_template.h"
#undef SHIFT
#endif
/* Test that BIT is enabled in CR4. If not, raise an illegal opcode
exception. This reduces the requirements for rare CR4 bits being
mapped into HFLAGS. */
void helper_cr4_testbit(CPUX86State *env, uint32_t bit)
{
if (unlikely((env->cr[4] & bit) == 0)) {
raise_exception_ra(env, EXCP06_ILLOP, GETPC());
}
}
target_ulong HELPER(rdrand)(CPUX86State *env)
{
Error *err = NULL;
target_ulong ret;
if (qemu_guest_getrandom(&ret, sizeof(ret), &err) < 0) {
qemu_log_mask(LOG_UNIMP, "rdrand: Crypto failure: %s",
error_get_pretty(err));
error_free(err);
/* Failure clears CF and all other flags, and returns 0. */
env->cc_src = 0;
return 0;
}
/* Success sets CF and clears all others. */
env->cc_src = CC_C;
return ret;
}
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