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05303: All sets in harddriv.c: Wrong colors on title screen and during gameplay. [Phil Bennett]

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m68000: The 68010 does not perform a read before write during a CLR instruction [Phil Bennett]


Sources:
http://www.opensource.apple.com/source/gcc/gcc-1765/gcc/config/m68k/m68k.c
"clr insns on 68000 read before writing. This isn't so on the 68010, but we have no TARGET_68010."

http://www.zophar.net/fileuploads/2/10544qufns/jag68k.txt
"The special thing about a CLR (on the 68000, fixed in the 68010 and onwards I believe) is, that the processor does a source read before doing a destination write."
This commit is contained in:
Phil Bennett 2013-09-22 09:55:41 +00:00
parent f9b6a0d8f4
commit 4be7cf079c
1 changed files with 6 additions and 6 deletions
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12
src/emu/cpu/m68000/m68k_in.c
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@ -3897,9 +3897,9 @@ M68KMAKE_OP(clr, 8, ., .)
{
UINT32 ea = M68KMAKE_GET_EA_AY_8;
if(CPU_TYPE_IS_010_LESS((mc68kcpu)->cpu_type))
if(CPU_TYPE_IS_000((mc68kcpu)->cpu_type))
{
m68ki_read_8((mc68kcpu), ea); /* the 68000 (and 010?) does a dummy read, the value is discarded */
m68ki_read_8((mc68kcpu), ea); /* the 68000 does a dummy read, the value is discarded */
}
m68ki_write_8((mc68kcpu), ea, 0);
@ -3926,9 +3926,9 @@ M68KMAKE_OP(clr, 16, ., .)
{
UINT32 ea = M68KMAKE_GET_EA_AY_16;
if(CPU_TYPE_IS_010_LESS((mc68kcpu)->cpu_type))
if(CPU_TYPE_IS_000((mc68kcpu)->cpu_type))
{
m68ki_read_16((mc68kcpu), ea); /* the 68000 (and 010?) does a dummy read, the value is discarded */
m68ki_read_16((mc68kcpu), ea); /* the 68000 does a dummy read, the value is discarded */
}
m68ki_write_16((mc68kcpu), ea, 0);
@ -3955,9 +3955,9 @@ M68KMAKE_OP(clr, 32, ., .)
{
UINT32 ea = M68KMAKE_GET_EA_AY_32;
if(CPU_TYPE_IS_010_LESS((mc68kcpu)->cpu_type))
if(CPU_TYPE_IS_000((mc68kcpu)->cpu_type))
{
m68ki_read_32((mc68kcpu), ea); /* the 68000 (and 010?) does a dummy read, the value is discarded */
m68ki_read_32((mc68kcpu), ea); /* the 68000 does a dummy read, the value is discarded */
}
m68ki_write_32((mc68kcpu), ea, 0);