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target/i386: validate SSE prefixes directly in the decoding table

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Many SSE and AVX instructions are only valid with specific prefixes
(none, 66, F3, F2).  Introduce a direct way to encode this in the
decoding table to avoid using decode groups too much.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2022-09-05 15:30:02 +02:00
parent 20581aadec
commit 55a3328669
2 changed files with 38 additions and 0 deletions
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37
target/i386/tcg/decode-new.c.inc
View file

@ -110,6 +110,22 @@
#define avx2_256 .vex_special = X86_VEX_AVX2_256, #define avx2_256 .vex_special = X86_VEX_AVX2_256,
#define P_00 1
#define P_66 (1 << PREFIX_DATA)
#define P_F3 (1 << PREFIX_REPZ)
#define P_F2 (1 << PREFIX_REPNZ)
#define p_00 .valid_prefix = P_00,
#define p_66 .valid_prefix = P_66,
#define p_f3 .valid_prefix = P_F3,
#define p_f2 .valid_prefix = P_F2,
#define p_00_66 .valid_prefix = P_00 | P_66,
#define p_00_f3 .valid_prefix = P_00 | P_F3,
#define p_66_f2 .valid_prefix = P_66 | P_F2,
#define p_00_66_f3 .valid_prefix = P_00 | P_66 | P_F3,
#define p_66_f3_f2 .valid_prefix = P_66 | P_F3 | P_F2,
#define p_00_66_f3_f2 .valid_prefix = P_00 | P_66 | P_F3 | P_F2,
static uint8_t get_modrm(DisasContext *s, CPUX86State *env) static uint8_t get_modrm(DisasContext *s, CPUX86State *env)
{ {
if (!s->has_modrm) { if (!s->has_modrm) {
@ -480,6 +496,23 @@ static bool decode_op(DisasContext *s, CPUX86State *env, X86DecodedInsn *decode,
return true; return true;
} }
static bool validate_sse_prefix(DisasContext *s, X86OpEntry *e)
{
uint16_t sse_prefixes;
if (!e->valid_prefix) {
return true;
}
if (s->prefix & (PREFIX_REPZ | PREFIX_REPNZ)) {
/* In SSE instructions, 0xF3 and 0xF2 cancel 0x66. */
s->prefix &= ~PREFIX_DATA;
}
/* Now, either zero or one bit is set in sse_prefixes. */
sse_prefixes = s->prefix & (PREFIX_REPZ | PREFIX_REPNZ | PREFIX_DATA);
return e->valid_prefix & (1 << sse_prefixes);
}
static bool decode_insn(DisasContext *s, CPUX86State *env, X86DecodeFunc decode_func, static bool decode_insn(DisasContext *s, CPUX86State *env, X86DecodeFunc decode_func,
X86DecodedInsn *decode) X86DecodedInsn *decode)
{ {
@ -491,6 +524,10 @@ static bool decode_insn(DisasContext *s, CPUX86State *env, X86DecodeFunc decode_
e->decode(s, env, e, &decode->b); e->decode(s, env, e, &decode->b);
} }
if (!validate_sse_prefix(s, e)) {
return false;
}
/* First compute size of operands in order to initialize s->rip_offset. */ /* First compute size of operands in order to initialize s->rip_offset. */
if (e->op0 != X86_TYPE_None) { if (e->op0 != X86_TYPE_None) {
if (!decode_op_size(s, e, e->s0, &decode->op[0].ot)) { if (!decode_op_size(s, e, e->s0, &decode->op[0].ot)) {

1
target/i386/tcg/decode-new.h
View file

@ -212,6 +212,7 @@ struct X86OpEntry {
X86CPUIDFeature cpuid:8; X86CPUIDFeature cpuid:8;
unsigned vex_class:8; unsigned vex_class:8;
X86VEXSpecial vex_special:8; X86VEXSpecial vex_special:8;
uint16_t valid_prefix:16;
bool is_decode:1; bool is_decode:1;
}; };