Build/arch cleanups, target/i386 fixes for 2024-05-10

[PULL 02/27] target/i386: fix operand size for DATA16 REX.W POPCNT

Paolo Bonzini posted 27 patches 6 months, 2 weeks ago

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Maintainers: "Alex Bennée" <alex.bennee@linaro.org>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Thomas Huth <thuth@redhat.com>, Wainer dos Santos Moschetta <wainersm@redhat.com>, Beraldo Leal <bleal@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Song Gao <gaosong@loongson.cn>, Jiaxun Yang <jiaxun.yang@flygoat.com>, Palmer Dabbelt <palmer@dabbelt.com>, Alistair Francis <alistair.francis@wdc.com>, Bin Meng <bmeng.cn@gmail.com>, Weiwei Li <liwei1518@gmail.com>, Daniel Henrique Barboza <dbarboza@ventanamicro.com>, Liu Zhiwei <zhiwei_liu@linux.alibaba.com>, Stefano Stabellini <sstabellini@kernel.org>, Anthony PERARD <anthony@xenproject.org>, Paul Durrant <paul@xen.org>, Peter Maydell <peter.maydell@linaro.org>, Richard Henderson <richard.henderson@linaro.org>, Eduardo Habkost <eduardo@habkost.net>, "Michael S. Tsirkin" <mst@redhat.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Halil Pasic <pasic@linux.ibm.com>, Christian Borntraeger <borntraeger@linux.ibm.com>, David Hildenbrand <david@redhat.com>, Stafford Horne <shorne@gmail.com>, Nicholas Piggin <npiggin@gmail.com>, Yoshinori Sato <ysato@users.sourceforge.jp>, Eric Farman <farman@linux.ibm.com>, Ilya Leoshkevich <iii@linux.ibm.com>, Gerd Hoffmann <kraxel@redhat.com>, Max Filippov <jcmvbkbc@gmail.com>, David Gibson <david@gibson.dropbear.id.au>, "Marc-André Lureau" <marcandre.lureau@redhat.com>, "Daniel P. Berrangé" <berrange@redhat.com>, "Dr. David Alan Gilbert" <dave@treblig.org>, "Edgar E. Iglesias" <edgar.iglesias@gmail.com>, Laurent Vivier <lvivier@redhat.com>, Peter Xu <peterx@redhat.com>, Fabiano Rosas <farosas@suse.de>

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[PULL 02/27] target/i386: fix operand size for DATA16 REX.W POPCNT

Posted by Paolo Bonzini 6 months, 2 weeks ago

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>
---
 target/i386/tcg/translate.c | 17 +----------------
 1 file changed, 1 insertion(+), 16 deletions(-)

diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
index 7d9f6b5c55b..5366dc32dd3 100644
--- a/target/i386/tcg/translate.c
+++ b/target/i386/tcg/translate.c
@@ -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);
-- 
2.45.0