[PATCH 19/28] tcg: Make use of bswap flags in tcg_gen_qemu_st_*

Richard Henderson posted 28 patches 3 years, 4 months ago
Maintainers: Andrzej Zaborowski <balrogg@gmail.com>, Aurelien Jarno <aurelien@aurel32.net>, Richard Henderson <richard.henderson@linaro.org>, Cornelia Huck <cohuck@redhat.com>, David Hildenbrand <david@redhat.com>, Palmer Dabbelt <palmer@dabbelt.com>, Aleksandar Rikalo <aleksandar.rikalo@syrmia.com>, "Philippe Mathieu-Daudé" <f4bug@amsat.org>, Jiaxun Yang <jiaxun.yang@flygoat.com>, Huacai Chen <chenhuacai@kernel.org>, Eduardo Habkost <ehabkost@redhat.com>, Thomas Huth <thuth@redhat.com>, Peter Maydell <peter.maydell@linaro.org>, Stefan Weil <sw@weilnetz.de>, Paolo Bonzini <pbonzini@redhat.com>, Alistair Francis <Alistair.Francis@wdc.com>, Yoshinori Sato <ysato@users.sourceforge.jp>
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[PATCH 19/28] tcg: Make use of bswap flags in tcg_gen_qemu_st_*
Posted by Richard Henderson 3 years, 4 months ago
By removing TCG_BSWAP_IZ we indicate that the input is
not zero-extended, and thus can remove an explicit extend.
By removing TCG_BSWAP_OZ, we allow the implementation to
leave high bits set, which will be ignored by the store.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/tcg-op.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/tcg/tcg-op.c b/tcg/tcg-op.c
index 702da7afb7..5dbcd1b0cf 100644
--- a/tcg/tcg-op.c
+++ b/tcg/tcg-op.c
@@ -2915,8 +2915,7 @@ void tcg_gen_qemu_st_i32(TCGv_i32 val, TCGv addr, TCGArg idx, MemOp memop)
         swap = tcg_temp_new_i32();
         switch (memop & MO_SIZE) {
         case MO_16:
-            tcg_gen_ext16u_i32(swap, val);
-            tcg_gen_bswap16_i32(swap, swap, TCG_BSWAP_IZ | TCG_BSWAP_OZ);
+            tcg_gen_bswap16_i32(swap, val, 0);
             break;
         case MO_32:
             tcg_gen_bswap32_i32(swap, val);
@@ -3013,12 +3012,10 @@ void tcg_gen_qemu_st_i64(TCGv_i64 val, TCGv addr, TCGArg idx, MemOp memop)
         swap = tcg_temp_new_i64();
         switch (memop & MO_SIZE) {
         case MO_16:
-            tcg_gen_ext16u_i64(swap, val);
-            tcg_gen_bswap16_i64(swap, swap, TCG_BSWAP_IZ | TCG_BSWAP_OZ);
+            tcg_gen_bswap16_i64(swap, val, 0);
             break;
         case MO_32:
-            tcg_gen_ext32u_i64(swap, val);
-            tcg_gen_bswap32_i64(swap, swap, TCG_BSWAP_IZ | TCG_BSWAP_OZ);
+            tcg_gen_bswap32_i64(swap, val, 0);
             break;
         case MO_64:
             tcg_gen_bswap64_i64(swap, val);
-- 
2.25.1


Re: [PATCH 19/28] tcg: Make use of bswap flags in tcg_gen_qemu_st_*
Posted by Peter Maydell 3 years, 4 months ago
On Mon, 14 Jun 2021 at 09:51, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> By removing TCG_BSWAP_IZ we indicate that the input is
> not zero-extended, and thus can remove an explicit extend.
> By removing TCG_BSWAP_OZ, we allow the implementation to
> leave high bits set, which will be ignored by the store.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

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

thanks
-- PMM