| Message ID | 20230307183503.2512684-13-richard.henderson@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | tcg: Remove tcg_const_* | expand |
Le 07/03/2023 à 19:34, Richard Henderson a écrit : > In theory this should never happen, as all such instructions > are illegal. This is checked in e.g. gen_lea_mode and > gen_ea_mode_fp but not here. In case something higher up > isn't checking modes properly, return NULL_QREG. This will > result in an illegal instruction exception being raised. NULL_QREG generates an address exception, not illegal instruction. > > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > --- > Cc: Laurent Vivier <laurent@vivier.eu> > --- > target/m68k/translate.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/target/m68k/translate.c b/target/m68k/translate.c > index 44c3ac0bc3..fc65dad190 100644 > --- a/target/m68k/translate.c > +++ b/target/m68k/translate.c > @@ -894,6 +894,10 @@ static TCGv gen_ea_mode(CPUM68KState *env, DisasContext *s, int mode, int reg0, > case 3: /* pc index+displacement. */ > goto do_indirect; > case 4: /* Immediate. */ > + /* Should never be used for an output or RMW input. */ > + if (what == EA_STORE || addrp) { Why do you check addrp? What happens for an instruction that provides addrp to SRC_EA() when it is used with immediate mode? In this case addrp is unused, but it should not trigger an exception. Thanks, Laurent > + return NULL_QREG; > + } > /* Sign extend values for consistency. */ > switch (opsize) { > case OS_BYTE:
On 3/9/23 04:32, Laurent Vivier wrote: > Le 07/03/2023 à 19:34, Richard Henderson a écrit : >> In theory this should never happen, as all such instructions >> are illegal. This is checked in e.g. gen_lea_mode and >> gen_ea_mode_fp but not here. In case something higher up >> isn't checking modes properly, return NULL_QREG. This will >> result in an illegal instruction exception being raised. > > NULL_QREG generates an address exception, not illegal instruction. > >> >> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> >> --- >> Cc: Laurent Vivier <laurent@vivier.eu> >> --- >> target/m68k/translate.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/target/m68k/translate.c b/target/m68k/translate.c >> index 44c3ac0bc3..fc65dad190 100644 >> --- a/target/m68k/translate.c >> +++ b/target/m68k/translate.c >> @@ -894,6 +894,10 @@ static TCGv gen_ea_mode(CPUM68KState *env, DisasContext *s, int >> mode, int reg0, >> case 3: /* pc index+displacement. */ >> goto do_indirect; >> case 4: /* Immediate. */ >> + /* Should never be used for an output or RMW input. */ >> + if (what == EA_STORE || addrp) { > > Why do you check addrp? > > What happens for an instruction that provides addrp to SRC_EA() when it is used with > immediate mode? > In this case addrp is unused, but it should not trigger an exception. Because addrp is *not* unused with SRC_EA. It is a signal for a read-modify-write operand and addrp will be passed to DEST_EA. r~
diff --git a/target/m68k/translate.c b/target/m68k/translate.c index 44c3ac0bc3..fc65dad190 100644 --- a/target/m68k/translate.c +++ b/target/m68k/translate.c @@ -894,6 +894,10 @@ static TCGv gen_ea_mode(CPUM68KState *env, DisasContext *s, int mode, int reg0, case 3: /* pc index+displacement. */ goto do_indirect; case 4: /* Immediate. */ + /* Should never be used for an output or RMW input. */ + if (what == EA_STORE || addrp) { + return NULL_QREG; + } /* Sign extend values for consistency. */ switch (opsize) { case OS_BYTE:
In theory this should never happen, as all such instructions are illegal. This is checked in e.g. gen_lea_mode and gen_ea_mode_fp but not here. In case something higher up isn't checking modes properly, return NULL_QREG. This will result in an illegal instruction exception being raised. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- Cc: Laurent Vivier <laurent@vivier.eu> --- target/m68k/translate.c | 4 ++++ 1 file changed, 4 insertions(+)