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1 | /************************************* |
2 | Little John GP32 |
3 | File : ncpu.S |
4 | Authors : FCA author |
5 | modified and adapted by Yoyo. |
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6 | timing fixed, missing opcodes added |
7 | and adapted for fceu by notaz, 2007. |
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8 | **************************************/ |
9 | |
10 | #include "ncpu.h" |
11 | |
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12 | /* emulate (some) dummy reads (may need that because they affect open bus) */ |
13 | #define DO_DUMMY_READS 1 |
14 | |
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15 | @@@ |
16 | @@@ Offets from REG_OP_TABLE |
17 | @@@ |
18 | #define OTOFFS_NES_RAM (nes_internal_ram - cpu_exec_table) |
19 | #define OTOFFS_NES_STACK (nes_stack - cpu_exec_table) |
20 | #define OTOFFS_NES_REGS (nes_registers - cpu_exec_table) |
21 | #define OTOFFS_PC_BASE (pc_base - cpu_exec_table) |
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22 | #define OTOFFS_IRQ_HOOK (MapIRQHook - cpu_exec_table) |
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23 | #define OTOFFS_TIMESTAMP (timestamp - cpu_exec_table) |
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24 | #define OTOFFS_X (X_ - cpu_exec_table) |
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25 | |
26 | @ fceu |
27 | #define FCEU_IQNMI 0x08 |
28 | #define FCEU_IQTEMP 0x80 |
29 | |
30 | |
31 | @@@@@@@@@@@@@@@@@@@@@@@@@@ |
32 | |
33 | |
34 | @ SECTION_FAST |
35 | SECTION_TEXT |
36 | ALIGN |
37 | |
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38 | /* |
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39 | bbbb: |
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40 | .ascii "ab_a: %04x" |
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41 | .byte 0x0a,0 |
42 | .align 4 |
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43 | stmfd sp!,{r0-r3,r12,lr} |
44 | mov r1,r0 |
45 | ldr r0,=bbbb |
46 | bl printf |
47 | ldmfd sp!,{r0-r3,r12,lr} |
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48 | */ |
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49 | |
50 | @@@ |
51 | @@@ r0 = Address (unbased) |
52 | @@@ uses REG_OP_TABLE; sets REG_PC; trashes r1,r2; keeps r0 |
53 | @@@ |
54 | .macro REBASE_PC |
55 | @ FIXME: do something with mem not in Page[]. |
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56 | @ stmfd sp!, {r0-r3,r12,lr} |
57 | @ mov r1, r0 |
58 | @ ldr r0, =bbbb |
59 | @ bl printf |
60 | @ ldmfd sp!, {r0-r3,r12,lr} |
61 | |
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62 | cmp r0, #0x2000 |
63 | ldrge r1, =Page |
64 | movge r2, r0, lsr #11 |
65 | ldrge r2, [r1, r2, lsl #2] |
66 | andlt r2, r0, #0xf800 |
67 | addlt r1, REG_OP_TABLE, #OTOFFS_NES_RAM |
68 | sublt r2, r1, r2 |
69 | str r2, [REG_OP_TABLE, #OTOFFS_PC_BASE] |
70 | add REG_PC, r2, r0 |
71 | .endm |
72 | |
73 | |
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74 | @ updates fceu "timestamp" variable |
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75 | @ loads cycles to reg, reg!=r1, trashes r1, kills flags |
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76 | .macro FLUSH_TIMESTAMP reg |
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77 | ands \reg, REG_CYCLE, #0xff |
78 | beq 1f |
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79 | ldr r1, [REG_OP_TABLE, #OTOFFS_TIMESTAMP] |
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80 | orr REG_CYCLE, REG_CYCLE, \reg, lsl #8 @ put cycles for do_irq_hook |
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81 | add r1, r1, \reg |
82 | bic REG_CYCLE, REG_CYCLE, #0xff |
83 | str r1, [REG_OP_TABLE, #OTOFFS_TIMESTAMP] |
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84 | 1: |
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85 | .endm |
86 | |
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87 | |
88 | @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ |
89 | @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ |
90 | @@@ |
91 | @@@ CYCLE_NEXT |
92 | @@@ |
93 |