diff options
| author | Philippe Mathieu-Daudé <philmd@linaro.org> | 2023-08-23 16:55:38 +0200 |
|---|---|---|
| committer | Richard Henderson <richard.henderson@linaro.org> | 2023-08-24 11:22:42 -0700 |
| commit | 9c40621584622078dcf47bb9add9a05925105130 (patch) | |
| tree | 302e406e8de16d7b1fe8b7d99ba790626cf24061 /tcg | |
| parent | 9296455697dbc423f0ca201f75d4e44bfcb68a5b (diff) | |
tcg/tcg-op: Document bswap32_i64() byte pattern
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230823145542.79633-5-philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'tcg')
| -rw-r--r-- | tcg/tcg-op.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/tcg/tcg-op.c b/tcg/tcg-op.c index ed0ab218a1..b56ae748b8 100644 --- a/tcg/tcg-op.c +++ b/tcg/tcg-op.c @@ -1822,6 +1822,14 @@ void tcg_gen_bswap16_i64(TCGv_i64 ret, TCGv_i64 arg, int flags) } } +/* + * bswap32_i64: 32-bit byte swap on the low bits of a 64-bit value. + * + * Byte pattern: xxxxabcd -> yyyydcba + * + * With TCG_BSWAP_IZ, x == zero, else undefined. + * With TCG_BSWAP_OZ, y == zero, with TCG_BSWAP_OS y == sign, else undefined. + */ void tcg_gen_bswap32_i64(TCGv_i64 ret, TCGv_i64 arg, int flags) { /* Only one extension flag may be present. */ @@ -1855,7 +1863,8 @@ void tcg_gen_bswap32_i64(TCGv_i64 ret, TCGv_i64 arg, int flags) } else { tcg_gen_shri_i64(t1, t1, 32); /* t1 = ....dc.. */ } - tcg_gen_or_i64(ret, t0, t1); /* ret = ssssdcba */ + tcg_gen_or_i64(ret, t0, t1); /* ret = ssssdcba (OS) */ + /* ....dcba (else) */ tcg_temp_free_i64(t0); tcg_temp_free_i64(t1); |