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

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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>
(cherry picked from commit 41c685dc59)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
(Mjt: drop removal of mo_64_32() helper function in target/i386/tcg/translate.c
 due to missing-in-8.2 v9.0.0-542-gaef4f4affde2
 "target/i386: remove now-converted opcodes from old decoder"
 which removed other user of it)
This commit is contained in:
Paolo Bonzini 2024-05-09 12:38:10 +02:00 committed by Michael Tokarev
parent 7d7b770bde
commit eb761b4ee5
1 changed files with 1 additions and 6 deletions
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7
target/i386/tcg/translate.c
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@ -6780,12 +6780,7 @@ static bool disas_insn(DisasContext *s, CPUState *cpu)
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);