Master blaster fix

git-svn-id: file:///home/notaz/opt/svn/fceu@111 be3aeb3a-fb24-0410-a615-afba39da0efa

diff --git a/ncpu.S b/ncpu.S
index d649f9a..0b79afb 100644 (file)
--- a/ncpu.S
+++ b/ncpu.S
@@ -264,18 +264,7 @@ bbbb:
        strb    r0, [REG_ADDR]
 .endm
 
-.macro READ_WRITE_3
-       .long   read_rom_byte
-       .long   read_rom_byte
-       .long   read_rom_byte
-       .long   read_rom_byte
-       .long   read_save_ram
-       .long   read_high_reg
-       .long   read_ppu_reg
-9999:
-.endm
-
-.macro READ_WRITE_4
+.macro READ_WRITE_W
        adr     lr, 1f
        ldr     pc, [pc, r3, lsl #2]
        nop
@@ -290,6 +279,22 @@ bbbb:
 1:
 .endm
 
+.macro READ_WRITE_3
+       .long   read_rom_byte
+       .long   read_rom_byte
+       .long   read_rom_byte
+       .long   read_rom_byte
+       .long   read_save_ram
+       .long   read_high_reg
+       .long   read_ppu_reg
+9999:
+       READ_WRITE_W            @ rmw first writes unmodified data
+.endm
+
+.macro READ_WRITE_4
+       READ_WRITE_W            @ and only then modified (Blaster Master)
+.endm
+
 @@@
 @@@ ½ñ¤­¹þ¤ß¤À¤±¤Î¾ì¹ç
 @@@
@@ -2877,12 +2882,13 @@ write_high_reg:
 write_save_ram:
 write_rom_byte:
 #ifndef DEBUG_ASM_6502
-       @ must preserve r3 for the callers too
+       @ must preserve r0 (data) and r3 for the callers
        str     REG_PC,     [REG_OP_TABLE, #(OTOFFS_NES_REGS + 0x0c)]   @ might get rebased
        str     REG_P_REST, [REG_OP_TABLE, #(OTOFFS_NES_REGS + 0x10)]   @ might set irq
        str     REG_CYCLE,  [REG_OP_TABLE, #(OTOFFS_NES_REGS + 0x1c)]   @ might get used
        mov     REG_PC, lr                      @ r7
        mov     REG_P_REST, r3                  @ r8
+       mov     REG_CYCLE, r0                   @ r11
 
        ldr     r2, =BWrite
        mov     r1, r0
@@ -2893,6 +2899,7 @@ write_rom_byte:
        ldr     REG_OP_TABLE, =cpu_exec_table   @ got trashed because was in r12
        mov     lr, REG_PC
        mov     r3, REG_P_REST
+       mov     r0, REG_CYCLE
        ldr     REG_PC,     [REG_OP_TABLE, #(OTOFFS_NES_REGS + 0x0c)]   @ might get rebased
        ldr     REG_P_REST, [REG_OP_TABLE, #(OTOFFS_NES_REGS + 0x10)]   @ might set irq
        ldr     REG_CYCLE,  [REG_OP_TABLE, #(OTOFFS_NES_REGS + 0x1c)]   @ might get used