| Message ID | 1462392752-17703-5-git-send-email-laurent@vivier.eu |
|---|---|
| State | New |
| Headers | show |
On 05/04/2016 10:11 AM, Laurent Vivier wrote: > Scaled index is not supported by 68000, 68008, and 68010. > > EA = (bd + PC) + Xn.SIZE*SCALE + od > > Ignore it: > > M68000 FAMILY PROGRAMMER’S REFERENCE MANUAL > 2.4 BRIEF EXTENSION WORD FORMAT COMPATIBILITY > > "If the MC68000 were to execute an instruction that > encoded a scaling factor, the scaling factor would be > ignored and would not access the desired memory address. > The earlier microprocessors do not recognize the brief > extension word formats implemented by newer processors. > Although they can detect illegal instructions, they do not > decode invalid encodings of the brief extension word formats > as exceptions." > > Signed-off-by: Laurent Vivier <laurent@vivier.eu> > --- > target-m68k/translate.c | 5 +++++ > 1 file changed, 5 insertions(+) Reviewed-by: Richard Henderson <rth@twiddle.net> r~
diff --git a/target-m68k/translate.c b/target-m68k/translate.c index c08f35d..a8830a8 100644 --- a/target-m68k/translate.c +++ b/target-m68k/translate.c @@ -313,6 +313,11 @@ static TCGv gen_lea_indexed(CPUM68KState *env, DisasContext *s, TCGv base) if ((ext & 0x800) == 0 && !m68k_feature(s->env, M68K_FEATURE_WORD_INDEX)) return NULL_QREG; + if (m68k_feature(s->env, M68K_FEATURE_M68000) && + !m68k_feature(s->env, M68K_FEATURE_SCALED_INDEX)) { + ext &= ~(3 << 9); + } + if (ext & 0x100) { /* full extension word format */ if (!m68k_feature(s->env, M68K_FEATURE_EXT_FULL))
Scaled index is not supported by 68000, 68008, and 68010. EA = (bd + PC) + Xn.SIZE*SCALE + od Ignore it: M68000 FAMILY PROGRAMMER’S REFERENCE MANUAL 2.4 BRIEF EXTENSION WORD FORMAT COMPATIBILITY "If the MC68000 were to execute an instruction that encoded a scaling factor, the scaling factor would be ignored and would not access the desired memory address. The earlier microprocessors do not recognize the brief extension word formats implemented by newer processors. Although they can detect illegal instructions, they do not decode invalid encodings of the brief extension word formats as exceptions." Signed-off-by: Laurent Vivier <laurent@vivier.eu> --- target-m68k/translate.c | 5 +++++ 1 file changed, 5 insertions(+)