[Qemu-devel] [PATCH] target-xtensa: fetch 3rd opcode byte only when needed

[Qemu-devel] [PATCH] target-xtensa: fetch 3rd opcode byte only when needed

[Max Filippov]

According to ISA, 3.5.4, third opcode byte should not be fetched for
2-byte instructions.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 target-xtensa/translate.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/target-xtensa/translate.c b/target-xtensa/translate.c
index c81450d..6a0177f 100644
--- a/target-xtensa/translate.c
+++ b/target-xtensa/translate.c
@@ -749,7 +749,7 @@ static void disas_xtensa_insn(DisasContext *dc)
 
     uint8_t b0 = ldub_code(dc->pc);
     uint8_t b1 = ldub_code(dc->pc + 1);
-    uint8_t b2 = ldub_code(dc->pc + 2);
+    uint8_t b2 = 0;
 
     static const uint32_t B4CONST[] = {
         0xffffffff, 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 16, 32, 64, 128, 256
@@ -764,6 +764,7 @@ static void disas_xtensa_insn(DisasContext *dc)
         HAS_OPTION(XTENSA_OPTION_CODE_DENSITY);
     } else {
         dc->next_pc = dc->pc + 3;
+        b2 = ldub_code(dc->pc + 2);
     }
 
     switch (OP0) {
-- 
1.7.7.6