[v2] target/arm: Convert a64 advsimd to decodetree (part 1)

[PATCH v2 06/67] target/arm: Verify sz=0 for Advanced SIMD scalar pairwise (fp16)

Posted by Richard Henderson 6 months ago

All of these insns have "if sz == '1' then UNDEFINED" in their pseudocode.
Fixes a RISU miscompare for invalid insn 0x5ef0c87a.

Fixes: 5c36d89567c ("arm/translate-a64: add all FP16 ops in simd_scalar_pairwise")
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/translate-a64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index 5455ae3685..0bdddb8517 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -8006,7 +8006,7 @@ static void disas_simd_scalar_pairwise(DisasContext *s, uint32_t insn)
     case 0x2f: /* FMINP */
         /* FP op, size[0] is 32 or 64 bit*/
         if (!u) {
-            if (!dc_isar_feature(aa64_fp16, s)) {
+            if ((size & 1) || !dc_isar_feature(aa64_fp16, s)) {
                 unallocated_encoding(s);
                 return;
             } else {
-- 
2.34.1

Re: [PATCH v2 06/67] target/arm: Verify sz=0 for Advanced SIMD scalar pairwise (fp16)

Posted by Peter Maydell 6 months ago

On Sat, 25 May 2024 at 00:22, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> All of these insns have "if sz == '1' then UNDEFINED" in their pseudocode.
> Fixes a RISU miscompare for invalid insn 0x5ef0c87a.
>
> Fixes: 5c36d89567c ("arm/translate-a64: add all FP16 ops in simd_scalar_pairwise")
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM