| Message ID | 20210730225507.2642827-1-f4bug@amsat.org |
|---|---|
| State | New |
| Headers | show |
| Series | target/mips: Remove JR opcode unused arguments | expand |
On 7/30/21 12:55 PM, Philippe Mathieu-Daudé wrote: > case OPC_JR: > - gen_compute_branch(ctx, op1, 4, rs, rd, sa, 4); > + gen_compute_branch(ctx, op1, 4, rs, 0, 0, 4); Reviewed-by: Richard Henderson <richard.henderson@linaro.org> r~
On 7/31/21 12:55 AM, Philippe Mathieu-Daudé wrote: > JR opcode (Jump Register) only takes 1 argument, $rs. > JALR (Jump And Link Register) takes 3: $rs, $rd and $hint. > > Commit 6af0bf9c7c3 added their processing into decode_opc() as: > > case 0x08 ... 0x09: /* Jumps */ > gen_compute_branch(ctx, op1 | EXT_SPECIAL, rs, rd, sa); > > having both opcodes handled in the same function: gen_compute_branch. > > Per JR encoding, both $rd and $hint ('sa') are decoded as zero. > > Later this code got extracted to decode_opc_special(), > commit 7a387fffce5 used definitions instead of magic values: > > case OPC_JR ... OPC_JALR: > gen_compute_branch(ctx, op1, rs, rd, sa); > > Finally commit 0aefa33318b moved OPC_JR out of decode_opc_special, > to a new 'decode_opc_special_legacy' function: > > @@ -15851,6 +15851,9 @@ static void decode_opc_special_legacy(CPUMIPSState *env, DisasContext *ctx) > + case OPC_JR: > + gen_compute_branch(ctx, op1, 4, rs, rd, sa); > + break; > > @@ -15933,7 +15936,7 @@ static void decode_opc_special(CPUMIPSState *env, DisasContext *ctx) > - case OPC_JR ... OPC_JALR: > + case OPC_JALR: > gen_compute_branch(ctx, op1, 4, rs, rd, sa); > break; > > Since JR is now handled individually, it is pointless to decode > and pass it unused arguments. Replace them by simple zero value > to avoid confusion with this opcode. > > Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> > --- > target/mips/tcg/translate.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) Thanks, applied to mips-next.
diff --git a/target/mips/tcg/translate.c b/target/mips/tcg/translate.c index 5b03545f099..bf71724f3f0 100644 --- a/target/mips/tcg/translate.c +++ b/target/mips/tcg/translate.c @@ -14203,7 +14203,7 @@ static void decode_opc_special_legacy(CPUMIPSState *env, DisasContext *ctx) break; #endif case OPC_JR: - gen_compute_branch(ctx, op1, 4, rs, rd, sa, 4); + gen_compute_branch(ctx, op1, 4, rs, 0, 0, 4); break; case OPC_SPIM: #ifdef MIPS_STRICT_STANDARD
JR opcode (Jump Register) only takes 1 argument, $rs. JALR (Jump And Link Register) takes 3: $rs, $rd and $hint. Commit 6af0bf9c7c3 added their processing into decode_opc() as: case 0x08 ... 0x09: /* Jumps */ gen_compute_branch(ctx, op1 | EXT_SPECIAL, rs, rd, sa); having both opcodes handled in the same function: gen_compute_branch. Per JR encoding, both $rd and $hint ('sa') are decoded as zero. Later this code got extracted to decode_opc_special(), commit 7a387fffce5 used definitions instead of magic values: case OPC_JR ... OPC_JALR: gen_compute_branch(ctx, op1, rs, rd, sa); Finally commit 0aefa33318b moved OPC_JR out of decode_opc_special, to a new 'decode_opc_special_legacy' function: @@ -15851,6 +15851,9 @@ static void decode_opc_special_legacy(CPUMIPSState *env, DisasContext *ctx) + case OPC_JR: + gen_compute_branch(ctx, op1, 4, rs, rd, sa); + break; @@ -15933,7 +15936,7 @@ static void decode_opc_special(CPUMIPSState *env, DisasContext *ctx) - case OPC_JR ... OPC_JALR: + case OPC_JALR: gen_compute_branch(ctx, op1, 4, rs, rd, sa); break; Since JR is now handled individually, it is pointless to decode and pass it unused arguments. Replace them by simple zero value to avoid confusion with this opcode. Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> --- target/mips/tcg/translate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)