ShuriZma
/
xemu
mirror of https://github.com/xemu-project/xemu.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

target/i386: fix operand size for DATA16 REX.W POPCNT 

According to the manual, 32-bit vs 64-bit is governed by REX.W
and REX ignores the 0x66 prefix.  This can be confirmed with this
program:

    #include <stdio.h>
    int main()
    {
       int x = 0x12340000;
       int y;
       asm("popcntl %1, %0" : "=r" (y) : "r" (x)); printf("%x\n", y);
       asm("mov $-1, %0; .byte 0x66; popcntl %1, %0" : "+r" (y) : "r" (x)); printf("%x\n", y);
       asm("mov $-1, %0; .byte 0x66; popcntq %q1, %q0" : "+r" (y) : "r" (x)); printf("%x\n", y);
    }

which prints 5/ffff0000/5 on real hardware and 5/ffff0000/ffff0000
on QEMU.

Cc: qemu-stable@nongnu.org
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2024-05-09 12:38:10 +02:00
parent 9f07e47a5e
commit 41c685dc59
1 changed files with 1 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
target/i386/tcg/translate.c
View File

@ -411,16 +411,6 @@ static inline MemOp mo_stacksize(DisasContext *s)
return CODE64(s) ? MO_64 : SS32(s) ? MO_32 : MO_16;
}
/* Select only size 64 else 32. Used for SSE operand sizes. */
static inline MemOp mo_64_32(MemOp ot)
{
#ifdef TARGET_X86_64
return ot == MO_64 ? MO_64 : MO_32;
#else
return MO_32;
#endif
}
/* Select size 8 if lsb of B is clear, else OT. Used for decoding
byte vs word opcodes. */
static inline MemOp mo_b_d(int b, MemOp ot)
@ -4545,12 +4535,7 @@ static void disas_insn_old(DisasContext *s, CPUState *cpu, int b)
modrm = x86_ldub_code(env, s);
reg = ((modrm >> 3) & 7) | REX_R(s);
if (s->prefix & PREFIX_DATA) {
ot = MO_16;
} else {
ot = mo_64_32(dflag);
}
ot = dflag;
gen_ldst_modrm(env, s, modrm, ot, OR_TMP0, 0);
gen_extu(ot, s->T0);
tcg_gen_mov_tl(cpu_cc_src, s->T0);