The-Homebrew-Cloud/Genesis-Plus-GX
2
0
Fork 0
mirror of https://github.com/ekeeke/Genesis-Plus-GX.git synced 2024-06-02 16:48:43 +02:00
Code Issues Packages Projects Releases Wiki Activity

[Core/CD] minor optimization of Word-RAM switching in 1M mode

Browse Source
This commit is contained in:
ekeeke 2023-11-18 18:01:01 +01:00
parent 8169f02496
commit 9b0b8d3afc
1 changed files with 13 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
core/cd_hw/scd.c
View File

@ -717,6 +717,15 @@ INLINE void word_ram_switch(uint8 mode)
*ptr2++=*ptr1++;
*ptr3++=*ptr1++;
}
/* SUB-CPU: $0C0000-$0DFFFF is mapped to Word-RAM 0 or 1 */
for (i=0x0c; i<0x0e; i++)
{
s68k.memory_map[i].read8 = NULL;
s68k.memory_map[i].read16 = NULL;
s68k.memory_map[i].write8 = NULL;
s68k.memory_map[i].write16 = NULL;
}
}
else
{
@ -860,10 +869,6 @@ static void scd_write_byte(unsigned int address, unsigned int data)
{
/* Word-RAM 0 data mapped at $0C0000-$0DFFFF */
s68k.memory_map[i].base = scd.word_ram[0] + ((i & 0x01) << 16);
s68k.memory_map[i].read8 = NULL;
s68k.memory_map[i].read16 = NULL;
s68k.memory_map[i].write8 = NULL;
s68k.memory_map[i].write16 = NULL;
}
/* writing 1 to RET bit in 1M mode returns Word-RAM to MAIN-CPU in 2M mode */
@ -903,10 +908,6 @@ static void scd_write_byte(unsigned int address, unsigned int data)
{
/* Word-RAM 1 data mapped at $0C0000-$0DFFFF */
s68k.memory_map[i].base = scd.word_ram[1] + ((i & 0x01) << 16);
s68k.memory_map[i].read8 = NULL;
s68k.memory_map[i].read16 = NULL;
s68k.memory_map[i].write8 = NULL;
s68k.memory_map[i].write16 = NULL;
}
}
@ -1131,10 +1132,6 @@ static void scd_write_word(unsigned int address, unsigned int data)
{
/* Word-RAM 0 data mapped at $0C0000-$0DFFFF */
s68k.memory_map[i].base = scd.word_ram[0] + ((i & 0x01) << 16);
s68k.memory_map[i].read8 = NULL;
s68k.memory_map[i].read16 = NULL;
s68k.memory_map[i].write8 = NULL;
s68k.memory_map[i].write16 = NULL;
}
/* writing 1 to RET bit in 1M mode returns Word-RAM to MAIN-CPU in 2M mode */
@ -1174,10 +1171,6 @@ static void scd_write_word(unsigned int address, unsigned int data)
{
/* Word-RAM 1 data mapped at $0C0000-$0DFFFF */
s68k.memory_map[i].base = scd.word_ram[1] + ((i & 0x01) << 16);
s68k.memory_map[i].read8 = NULL;
s68k.memory_map[i].read16 = NULL;
s68k.memory_map[i].write8 = NULL;
s68k.memory_map[i].write16 = NULL;
}
}