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77fa2964f1
Applerm-II/6502.S
Takashi Toyoshima 77fa2964f1 Bug fix: stack is hard :( 
SP should wrap correctly on push and pop
2014-12-08 02:43:05 +09:00

1964 lines
24 KiB
ArmAsm
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.syntax unified
.cpu cortex-m0
.align 2
.thumb
.thumb_func
.text
.extern cpu6502_dump
.extern cpu6502_load
.extern cpu6502_store
.extern prn
.macro prn reg
push {r0-r3}
mov r0, \reg
bl prn
pop {r0-r3}
.endm
#define T0 r4
#define T1 r5
#define PC r6
#define SR r7
#define RA r8
#define RX r9
#define RY r10
#define SP r11
#define TZ r12
#define ADDR r12
#define FLAG_N (1 << 7)
#define FLAG_V (1 << 6)
#define FLAG_X (1 << 5)
#define FLAG_B (1 << 4)
#define FLAG_D (1 << 3)
#define FLAG_I (1 << 2)
#define FLAG_Z (1 << 1)
#define FLAG_C (1 << 0)
.macro _ldb
.ifdef USE_FRAMEPOINTER
// If -fomit-frame-pointer is not specified, save and restore r12 here.
push {r1}
mov r1, r12
push {r1}
.endif
bl cpu6502_load
.ifdef USE_FRAMEPOINTER
pop {r1}
mov r12, r1
pop {r1}
.endif
.endm
.macro _ldw
mov T0, r0
bl cpu6502_load
mov T1, r0
adds r0, T0, #1
bl cpu6502_load
lsls r0, r0, #8
adds r0, r0, T1
.endm
.macro _stb
.ifdef USE_FRAMEPOINTER
push {r1}
mov r1, r12
push {r1}
.endif
bl cpu6502_store
.ifdef USE_FRAMEPOINTER
pop {r1}
mov r12, r1
pop {r1}
.endif
.endm
.macro _stw
mov T0, r0
mov T1, r1
bl cpu6502_store
adds r0, T0, #1
lsrs r1, T1, #8
bl cpu6502_store
.endm
.macro _pushb reg
mov r0, SP
mov r1, \reg
_stb
mov r0, SP
subs r0, r0, #1
cmp r0, #0xff
bne 1f
lsls r0, r0, #1
adds r0, r0, #1
1:
mov SP, r0
.endm
.macro _pushw reg
mov r0, SP
mov r1, \reg
lsrs r1, r1, #8
_stb
mov r0, SP
subs r0, r0, #1
cmp r0, #0xff
bne 1f
lsls r0, r0, #1
adds r0, r0, #1
1:
mov SP, r0
mov r1, \reg
_stb
mov r0, SP
subs r0, r0, #1
cmp r0, #0xff
bne 1f
lsls r0, r0, #1
adds r0, r0, #1
1:
mov SP, r0
.endm
.macro _popb
mov r0, SP
adds r0, r0, #1
lsrs r1, r0, #10
bcc 1f
lsrs r0, r0, #1
1:
mov SP, r0
_ldb
.endm
.macro _popw
mov r0, SP
adds r0, r0, #1
lsrs r1, r0, #10
bcc 1f
lsrs r0, r0, #1
1:
mov SP, r0
_ldb
mov T0, r0
mov r0, SP
adds r0, r0, #1
lsrs r1, r0, #10
bcc 1f
lsrs r0, r0, #1
1:
mov SP, r0
_ldb
lsls r0, r0, #8
adds r0, r0, T0
.endm
.macro _decode
bl dump
mov r0, PC
_ldb
lsls r1, r0, #2
ldr r2, 1f
adds r3, r2, r1
ldr r1, [r3]
mov pc, r1
.align 4
1:
.long op_table
.endm
.macro _fromAbsb
adds PC, PC, #2
subs r0, PC, #1
_ldw
mov ADDR, r0
_ldb
.endm
.macro _fromAbsoluteIndexed reg
adds PC, PC, #2
subs r0, PC, #1
_ldw
add r0, r0, \reg
mov ADDR, r0
_ldb
.endm
.macro _fromImmb
adds PC, PC, #1
mov r0, PC
_ldb
.endm
.macro _fromIndexedIndirect
_fromImmb
mov r1, RX
adds r0, r0, R1
uxtb r0, r0
mov T0, r0
_ldb
mov T1, r0
adds r0, T0, #1
uxtb r0, r0
_ldb
lsls r0, r0, #8
adds r0, r0, T1
mov ADDR, r0
_ldb
.endm
.macro _fromIndirectIndex
_fromImmb
mov T0, r0
_ldb
mov T1, r0
mov r0, T0
adds r0, r0, #1
uxtb r0, r0
_ldb
lsls r0, r0, #8
add r0, r0, T1
add r0, r0, RY
mov ADDR, r0
_ldb
.endm
.macro _fromReg reg
mov r0, \reg
.endm
.macro _fromZero
_fromImmb
mov ADDR, r0
_ldb
.endm
.macro _fromZeroIndex reg
_fromImmb
add r0, r0, \reg
uxtb r0, r0
mov ADDR, r0
_ldb
.endm
.macro _toAbsb
adds r0, PC, #1
mov TZ, T0
_ldw
mov r1, TZ
_stb
adds PC, PC, #3
.endm
.macro _toAbsoluteIndexed reg
adds r0, PC, #1
_ldw
add r0, r0, \reg
mov r1, T0
_stb
adds PC, PC, #3
.endm
.macro _toAddr
mov r0, ADDR
mov r1, T0
_stb
.endm
.macro _toIndexedIndirect
adds r0, PC, #1
_ldb
mov r1, RX
adds r0, r0, R1
uxtb r0, r0
mov T1, r0
_ldb
mov TZ, r0
adds r0, T1, #1
uxtb r0, r0
_ldb
lsls r0, r0, #8
add r0, r0, TZ
mov r1, T0
_stb
adds PC, PC, #2
.endm
.macro _toIndirectIndex
adds r0, PC, #1
_ldb
mov T1, r0
_ldb
mov TZ, r0
adds r0, T1, #1
uxtb r0, r0
_ldb
lsls r0, r0, #8
add r0, r0, TZ
add r0, r0, RY
mov r1, T0
_stb
adds PC, PC, #2
.endm
.macro _toReg reg
mov \reg, T0
.endm
.macro _toZero
adds r0, PC, #1
_ldb
mov r1, T0
_stb
adds PC, PC, #2
.endm
.macro _toZeroIndex reg
adds r0, PC, #1
_ldb
add r0, r0, \reg
uxtb r0, r0
mov r1, T0
_stb
adds PC, PC, #2
.endm
.macro __cl flag
movs T0, #\flag
bics SR, SR, T0
.endm
.macro __se flag
movs T0, #\flag
orrs SR, SR, T0
.endm
.macro _flag_nz
__cl (FLAG_N | FLAG_Z)
movs r0, r0
bne 1f
__se FLAG_Z
1:
movs r1, #FLAG_N
tst r0, r1
beq 1f
__se FLAG_N
1:
.endm
.macro _clx flag
__cl \flag
adds PC, PC, #1
.endm
.macro _sex flag
__se \flag
adds PC, PC, #1
.endm
.macro _adc
mov r1, RA
add r1, r1, r0
movs r2, #FLAG_C
tst SR, r2
beq 1f
adds r1, r1, #1
1:
movs r2, #FLAG_D
tst SR, r2
beq 1f
movs r2, #0x0f
ands r1, r1, r2
mov T0, RA
lsrs T0, T0, #8
mov T1, r0
lsrs T1, T1, #8
adds r2, T0, T1
cmp r1, #10
blo 2f
subs r1, r1, #10
adds r2, r2, #1
2:
cmp r2, #10
blo 2f
adds r2, r2, #6
2:
lsls r2, r2, #8
adds r1, r1, r2
1:
__cl (FLAG_N | FLAG_Z | FLAG_C | FLAG_V)
uxtb r2, r1
movs r2, r2
bne 1f
__se FLAG_Z
1:
movs r3, #FLAG_N
tst r2, r3
beq 1f
__se FLAG_N
1:
lsrs r1, r1, #9
bcc 1f
__se FLAG_C
1:
mov r1, RA
eors r0, r1, r0
mvns r0, r0
eors r1, r1, r2
ands r0, r0, r1
lsrs r0, r0, #8
bcc 1f
__se FLAG_V
1:
mov RA, r2
adds PC, PC, #1
.endm
.macro _asl
__cl (FLAG_N | FLAG_Z | FLAG_C)
movs r1, #FLAG_N
tst r0, r1
beq 1f
bics r0, r0, r1
__se FLAG_C
1:
lsls r0, r0, #1
bne 1f
__se FLAG_Z
1:
tst r0, r1
beq 1f
__se FLAG_N
1:
mov T0, r0
adds PC, PC, #1
.endm
.macro _bit
__cl (FLAG_N | FLAG_Z | FLAG_V)
mov r1, RA
ands r0, r1, r0
bne 1f
__se FLAG_Z
1:
movs r1, #FLAG_N
tst r0, r1
beq 1f
__se FLAG_N
1:
movs r1, #0x40
tst r0, r1
beq 1f
__se FLAG_V
1:
adds PC, PC, #1
.endm
.macro _bxc reg
adds PC, PC, #2
movs r0, #\reg
tst SR, r0
bne 1f
_bxx
1:
.endm
.macro _bxs reg
adds PC, PC, #2
movs r0, #\reg
tst SR, r0
beq 1f
_bxx
1:
.endm
.macro _bxx
subs r0, PC, #1
_ldb
sxtb r0, r0
add PC, PC, r0
.endm
.macro _cp reg
__cl (FLAG_N | FLAG_Z | FLAG_C)
mov r1, \reg
subs r2, r1, r0
sxtb r2, r2
subs r0, r1, r0
bmi 1f
__se FLAG_C
1:
sxtb r0, r0
movs r0, r0
bpl 1f
__se FLAG_N
b 2f
1:
bne 2f
__se FLAG_Z
2:
adds PC, PC, #1
.endm
.macro _dec
subs r0, r0, #1
uxtb r0, r0
_flag_nz
mov T0, r0
adds PC, PC, #1
.endm
.macro _inc
adds r0, r0, #1
uxtb r0, r0
_flag_nz
mov T0, r0
adds PC, PC, #1
.endm
.macro _jmp
mov PC, r0
.endm
.macro _ld reg
mov \reg, r0
_flag_nz
adds PC, PC, #1
.endm
.macro _lop op
mov r1, RA
\op r0, r1, r0
mov RA, r0
_flag_nz
adds PC, PC, #1
.endm
.macro _lsr
__cl (FLAG_N | FLAG_Z | FLAG_C)
movs r1, #0x01
tst r0, r1
beq 1f
__se FLAG_C
1:
lsrs r0, r0, #1
bne 1f
__se FLAG_Z
1:
movs r1, #FLAG_N
tst r0, r1
beq 1f
__se FLAG_N
1:
mov T0, r0
adds PC, PC, #1
.endm
.macro _nop
adds PC, PC, #1
.endm
.macro _rol
movs r2, #FLAG_C
ands r2, SR, r2
__cl (FLAG_N | FLAG_Z | FLAG_C)
movs r1, #FLAG_N
tst r0, r1
beq 1f
__se FLAG_C
1:
lsls r0, r0, #1
uxtb r0, r0
adds r0, r0, r2
bne 1f
__se FLAG_Z
1:
tst r0, r1
beq 1f
__se FLAG_N
1:
mov T0, r0
adds PC, PC, #1
.endm
.macro _ror
movs r2, #FLAG_C
ands r2, SR, r2
lsls r2, r2, #7
__cl (FLAG_N | FLAG_Z | FLAG_C)
movs r1, #0x01
tst r0, r1
beq 1f
__se FLAG_C
1:
lsrs r0, r0, #1
adds r0, r0, r2
bne 1f
__se FLAG_Z
1:
movs r1, #FLAG_N
tst r0, r1
beq 1f
__se FLAG_N
1:
mov T0, r0
adds PC, PC, #1
.endm
.macro _rti
_popb
mov SR, r0
_popw
mov PC, r0
.endm
.macro _sbc
mov r1, RA
subs r1, r1, r0
movs r2, #FLAG_C
tst SR, r2
bne 1f
subs r1, r1, #1
1:
movs r2, #FLAG_D
tst SR, r2
beq 1f
movs r2, #0x1f
ands r1, r1, r2
mov T0, RA
lsrs T0, T0, #8
mov T1, r0
lsrs T1, T1, #8
subs r2, T0, T1
cmp r1, #10
blo 2f
subs r1, r1, #6
subs r2, r2, #1
2:
movs r3, #0x1f
ands r2, r2, r3
cmp r2, #10
blo 2f
adds r2, r2, #6
2:
lsls r2, r2, #8
adds r1, r1, r2
1:
__cl (FLAG_N | FLAG_Z | FLAG_C | FLAG_V)
uxtb r2, r1
movs r2, r2
bne 1f
__se FLAG_Z
1:
movs r3, #FLAG_N
tst r2, r3
beq 1f
__se FLAG_N
1:
lsrs r1, r1, #9
bcs 1f
__se FLAG_C
1:
mov r1, RA
eors r0, r1, r0
eors r1, r1, r2
ands r0, r0, r1
lsrs r0, r0, #8
bcc 1f
__se FLAG_V
1:
mov RA, r2
adds PC, PC, #1
.endm
.macro _t from to
mov r0, \from
mov \to, r0
_flag_nz
adds PC, PC, #1
.endm
.macro _resume
ldr r0, =#r_pc
ldr PC, [r0]
ldr r0, =#r_sr
ldr SR, [r0]
ldr r0, =#r_a
ldr T0, [r0]
mov RA, T0
ldr r0, =#r_x
ldr T0, [r0]
mov RX, T0
ldr r0, =#r_y
ldr T0, [r0]
mov RY, T0
ldr r0, =#r_sp
ldr T0, [r0]
mov SP, T0
ldr T0, =#op_table
.endm
.macro _suspend
ldr r0, =#r_pc
str PC, [r0]
ldr r0, =#r_sr
str SR, [r0]
ldr r0, =#r_a
mov T0, RA
str T0, [r0]
ldr r0, =#r_x
mov T0, RX
str T0, [r0]
ldr r0, =#r_y
mov T0, RY
str T0, [r0]
ldr r0, =#r_sp
mov T0, SP
str T0, [r0]
.endm
// NOP
op02:
op03:
op04:
op07:
op0b:
op0c:
op0f:
op12:
op13:
op14:
op17:
op1a:
op1b:
op1c:
op1f:
op22:
op23:
op27:
op2b:
op2f:
op32:
op33:
op34:
op37:
op3a:
op3b:
op3c:
op3f:
op42:
op43:
op44:
op47:
op4b:
op4f:
op52:
op53:
op54:
op57:
op5a:
op5b:
op5c:
op5f:
op62:
op63:
op64:
op67:
op6b:
op6f:
op72:
op73:
op74:
op77:
op7a:
op7b:
op7c:
op7f:
op80:
op82:
op83:
op87:
op89:
op8b:
op8f:
op93:
op97:
op9b:
op9c:
op9e:
op9f:
opa3:
opa7:
opab:
opaf:
opb2:
opb3:
opb7:
opbb:
opbf:
opc2:
opc3:
opc7:
opcb:
opcf:
opd2:
opd3:
opd4:
opd7:
opda:
opdb:
opdc:
opdf:
ope2:
ope3:
ope7:
opea:
opeb:
opef:
opf2:
opf3:
opf4:
opf7:
opfa:
opfb:
opfc:
opff:
_nop
_decode
op00: // BRK
adds T0, PC, #2
_pushw T0
_pushb SR
movs r0, #0xff
lsls r0, r0, #8
adds r0, r0, #0xfe
_ldw
mov PC, r0
__se FLAG_I
_decode
op01: // ORA - (Indirect, X)
_fromIndexedIndirect
_lop orrs
_decode
op05: // ORA - Zero Page
_fromZero
_lop orrs
_decode
op06: // ASL - Zero Page
_fromZero
_asl
_toAddr
_decode
op08: // PHP
_pushb SR
adds PC, PC, #1
_decode
op09: // ORA - Immediate
_fromImmb
_lop orrs
_decode
op0a: // ASL - Accumulator
_fromReg RA
_asl
_toReg RA
_decode
op0d: // ORA - Absolute
_fromAbsb
_lop orrs
_decode
op0e: // ASL - Absolute
_fromAbsb
_asl
_toAddr
_decode
op10: // BPL (N==0)
_bxc FLAG_N
_decode
op11: // ORA - (Indirect), Y
_fromIndirectIndex
_lop orrs
_decode
op15: // ORA - Zero Page, X
_fromZeroIndex RX
_lop orrs
_decode
op16: // ASL - Zero Page, X
_fromZeroIndex RX
_asl
_toAddr
_decode
op18: // CLC
_clx FLAG_C
_decode
op19: // ORA - Absolute, Y
_fromAbsoluteIndexed RY
_lop orrs
_decode
op1d: // ORA - Absolute, X
_fromAbsoluteIndexed RX
_lop orrs
_decode
op1e: // ASL - Absolute, X
_fromAbsoluteIndexed RX
_asl
_toAddr
_decode
op20: // JSR
adds T0, PC, #2
_pushw T0
adds r0, PC, #1
_ldw
mov PC, r0
_decode
op21: // AND - (Indirect, X)
_fromIndexedIndirect
_lop ands
_decode
op24: // BIT - Zero Page
_fromZero
_bit
_decode
op25: // AND - Zero Page
_fromZero
_lop ands
_decode
op26: // ROR - Zero Page
_fromZero
_ror
_toAddr
_decode
op28: // PLP
_popb
mov SR, r0
__se (FLAG_X | FLAG_B)
adds PC, PC, #1
_decode
op29: // AND - Immediate
_fromImmb
_lop ands
_decode
op2a: // ROR - Accumulator
_fromReg RA
_ror
_toReg RA
_decode
op2c: // BIT - Absolute
_fromAbsb
_bit
_decode
op2d: // AND - Absolute
_fromAbsb
_lop ands
_decode
op2e: // ROL - Absolute
_fromAbsb
_rol
_toAddr
_decode
op30: // BMI (N==1)
_bxs FLAG_N
_decode
op31: // AND - (Indirect), Y
_fromIndirectIndex
_lop ands
_decode
op35: // AND - Zero Page, X
_fromZeroIndex RX
_lop ands
_decode
op36: // ROL - Zero Page, X
_fromZeroIndex RX
_rol
_toAddr
_decode
op38: // SEC
_sex FLAG_C
_decode
op39: // AND - Absolute, Y
_fromAbsoluteIndexed RY
_lop ands
_decode
op3d: // AND - Absolute, X
_fromAbsoluteIndexed RX
_lop ands
_decode
op3e: // ROL - Absolute, X
_fromAbsoluteIndexed RX
_rol
_toAddr
_decode
op40: // RTI
_rti
_decode
op41: // EOR - (Indirect), X
_fromIndexedIndirect
_lop eors
_decode
op45: // EOR - Zero Page
_fromZero
_lop eors
_decode
op46: // LSR - Zero Page
_fromZero
_lsr
_toAddr
_decode
op48: // PHA
_pushb RA
adds PC, PC, #1
_decode
op49: // EOR - Immediate
_fromImmb
_lop eors
_decode
op4a: // LSR - Accumulator
_fromReg RA
_lsr
_toReg RA
_decode
op4c: // JMP - Absolute
adds r0, PC, #1
_ldw
_jmp
_decode
op4d: // EOR - Absolute
_fromAbsb
_lop eors
_decode
op4e: // LSR - Absolute
_fromAbsb
_lsr
_toAddr
_decode
op50: // BVC (V==0)
_bxc FLAG_V
_decode
op51: // EOR - (Indirect), Y
_fromIndirectIndex
_lop eors
_decode
op55: // EOR - Zero Page, X
_fromZeroIndex RX
_lop eors
_decode
op56: // LSR - Zero Page, X
_fromZeroIndex RX
_lsr
_toAddr
_decode
op58: // CLI
_clx FLAG_I
_decode
op59: // EOR - Absolute, Y
_fromAbsoluteIndexed RY
_lop eors
_decode
op5d: // EOR - Absolute, X
_fromAbsoluteIndexed RX
_lop eors
_decode
op5e: // LSR - Absolute, X
_fromAbsoluteIndexed RX
_lsr
_toAddr
_decode
op60: // RTS
_popw
adds PC, r0, #1
_decode
op61: // ADC - (Indirect, X)
_fromIndexedIndirect
_adc
_decode
op65: // ADC - Zero Page
_fromZero
_adc
_decode
op66: // ROR - Zero Page
_fromZero
_ror
_toAddr
_decode
op68: // PLA
_popb
_flag_nz
mov RA, r0
adds PC, PC, #1
_decode
op69: // ADC - Immediate
_fromImmb
_adc
_decode
op6a: // ROR - Accumulator
_fromReg RA
_ror
_toReg RA
_decode
op6c: // JMP - Indirect
adds r0, PC, #1
_ldw
_ldw
_jmp
_decode
op6d: // ADC - Absolute
_fromAbsb
_adc
_decode
op6e: // ROR - Absolute
_fromAbsb
_ror
_toAddr
_decode
op70: // BVS (V==1)
_bxs FLAG_V
_decode
op71: // ADC - (Indirect), Y
_fromIndirectIndex
_adc
_decode
op75: // ADC - Zero Page, X
_fromZeroIndex RX
_adc
_decode
op76: // ROR - Zero Page, X
_fromZeroIndex RX
_ror
_toAddr
_decode
op78: // SEI
_sex FLAG_I
_decode
op79: // ADC - Absolute, Y
_fromAbsoluteIndexed RY
_adc
_decode
op7d: // ADC - Absolute, X
_fromAbsoluteIndexed RX
_adc
_decode
op7e: // ROR - Absolute, X
_fromAbsoluteIndexed RX
_ror
_decode
op81: // STA - (Indirect, X)
mov T0, RA
_toIndexedIndirect
_decode
op84: // STY - Zero Page
mov T0, RY
_toZero
_decode
op85: // STA - Zero Page
mov T0, RA
_toZero
_decode
op86: // STX - Zero Page
mov T0, RX
_toZero
_decode
op88: // DEY
_fromReg RY
_dec
_toReg RY
_decode
op8a: // TXA
_t RX, RA
_decode
op8c: // STY - Absolute
mov T0, RY
_toAbsb
_decode
op8d: // STA - Absolute
mov T0, RA
_toAbsb
_decode
op8e: // STX - Absolute
mov T0, RX
_toAbsb
_decode
op90: // BCC (C==0)
_bxc FLAG_C
_decode
op91: // STA - (Indirect), Y
mov T0, RA
_toIndirectIndex
_decode
op92: // STA - Zero Page, X
mov T0, RA
_toZeroIndex RX
_decode
op94: // STY - Zero Page, X
mov T0, RY
_toZeroIndex RX
_decode
op95: // STA - Zero Page, X
mov T0, RA
_toZeroIndex RX
_decode
op96: // STX - Zero Page, Y
mov T0, RX
_toZeroIndex RY
_decode
op98: // TYA
_t RY, RA
_decode
op99: // STA - Absolute, Y
mov T0, RA
_toAbsoluteIndexed RY
_decode
op9a: // TXS
movs r0, #1
lsls r0, r0, #8
add r0, RX, r0
mov SP, r0
adds PC, PC, #1
_decode
op9d: // STA - Absolute, X
mov T0, RA
_toAbsoluteIndexed RX
_decode
opa0: // LDY - Immediate
_fromImmb
_ld RY
_decode
opa1: // LDA - (Indirect, X)
_fromIndexedIndirect
_ld RA
_decode
opa2: // LDX - Immediate
_fromImmb
_ld RX
_decode
opa4: // LDY - Zero Page
_fromZero
_ld RY
_decode
opa5: // LDA - Zero Page
_fromZero
_ld RA
_decode
opa6: // LDX - Zero Page
_fromZero
_ld RX
_decode
opa8: // TAY
_t RA, RY
_decode
opa9: // LDA - Immediate
_fromImmb
_ld RA
_decode
opaa: // TAX
_t RA, RX
_decode
opac: // LDY - Absolute
_fromAbsb
_ld RY
_decode
opad: // LDA - Absolute
_fromAbsb
_ld RA
_decode
opae: // LDX - Absolute
_fromAbsb
_ld RX
_decode
opb0: // BCS (C==1)
_bxs FLAG_C
_decode
opb1: // LDA - (Indirect), Y
_fromIndirectIndex
_ld RA
_decode
opb4: // LDY - Zero Page, X
_fromZeroIndex RX
_ld RY
_decode
opb5: // LDA - Zero Page, X
_fromZeroIndex RX
_ld RA
_decode
opb6: // LDX - Zero Page, Y
_fromZeroIndex RY
_ld RX
_decode
opb8: // CLV
_clx FLAG_V
_decode
opb9: // LDA - Absolute, Y
_fromAbsoluteIndexed RY
_ld RA
_decode
opba: // TSX
_t SP, RX
mov r0, RX
uxtb r0, r0
mov RX, r0
_decode
opbc: // LDY - Absolute, X
_fromAbsoluteIndexed RX
_ld RY
_decode
opbd: // LDA - Absolute, X
_fromAbsoluteIndexed RX
_ld RA
_decode
opbe: // LDX - Absolute, Y
_fromAbsoluteIndexed RY
_ld RX
_decode
opc0: // CPY - Immediate
_fromImmb
_cp RY
_decode
opc1: // CMP - (Indirect, X)
_fromIndexedIndirect
_cp RA
_decode
opc4: // CPY - Zero Page
_fromZero
_cp RY
_decode
opc5: // CMP - Zero Page
_fromZero
_cp RA
_decode
opc6: // DEC - Zero Page
_fromZero
_dec
_toAddr
_decode
opc8: // INY
_fromReg RY
_inc
_toReg RY
_decode
opc9: // CMP - Immediate
_fromImmb
_cp RA
_decode
opca: // DEX
_fromReg RX
_dec
_toReg RX
_decode
opcc: // CPY - Absolute
_fromAbsb
_cp RY
_decode
opcd: // CMP - Absolute
_fromAbsb
_cp RA
_decode
opce: // DEC - Absolute
_fromAbsb
_dec
_toAddr
_decode
opd0: // BNE (Z==0)
_bxc FLAG_Z
_decode
opd1: // CMP - (Indirect), Y
_fromIndirectIndex
_cp RA
_decode
opd5: // CMP - Zero Page, X
_fromZeroIndex RX
_cp RA
_decode
opd6: // DEC - Zero Page, X
_fromZeroIndex RX
_dec
_toAddr
_decode
opd8: // CLD
_clx FLAG_D
_decode
opd9: // CMP - Absolute, Y
_fromAbsoluteIndexed RY
_cp RA
_decode
opdd: // CMP - Absolute, X
_fromAbsoluteIndexed RX
_cp RA
_decode
opde: // DEC - Absolute, X
_fromAbsoluteIndexed RX
_dec
_toAddr
_decode
ope0: // CPX - Immediate
_fromImmb
_cp RX
_decode
ope1: // SBC - (Indirect, X)
_fromIndexedIndirect
_sbc
_decode
ope4: // CPX - Zero Page
_fromZero
_cp RX
_decode
ope5: // SBC - Zero Page
_fromZero
_sbc
_decode
ope6: // INC - Zero Page
_fromZero
_inc
_toAddr
_decode
ope8: // INX
_fromReg RX
_inc
_toReg RX
_decode
ope9: // SBC - Immediate
_fromImmb
_sbc
_decode
opec: // CPX - Absolute
_fromAbsb
_cp RX
_decode
oped: // SBC - Absolute
_fromAbsb
_sbc
_decode
opee: // INC - Absolute
_fromAbsb
_inc
_toAddr
_decode
opf0: // BEQ (Z==1)
_bxs FLAG_Z
_decode
opf1: // SBC - (Indirect), Y
_fromIndirectIndex
_sbc
_decode
opf5: // SBC - Zero Page, X
_fromZeroIndex RX
_sbc
_decode
opf6: // INC - Zero Page, X
_fromZeroIndex RX
_inc
_toAddr
_decode
opf8: // SED
_sex FLAG_D
_decode
opf9: // SBC - Absolute, Y
_fromAbsoluteIndexed RY
_sbc
_decode
opfd: // SBC - Absolute, X
_fromAbsoluteIndexed RX
_sbc
_decode
opfe: // INC - Absolute, X
_fromAbsoluteIndexed RX
_inc
_toAddr
_decode
.global cpu6502_reset
.type cpu6502_reset, %function
cpu6502_reset:
push {r4-r7,lr}
movs r4, #0x00
movs r5, #0x01
lsls r5, r5, #8
adds r5, r5, #0xff
movs r6, #0x30
ldr r7, =#r_a
str r4, [r7]
ldr r7, =#r_x
str r4, [r7]
ldr r7, =#r_y
str r4, [r7]
ldr r7, =#r_sp
str r5, [r7]
ldr r7, =#r_sr
str r6, [r7]
ldr r0, =#0xfffc
_ldw
ldr r7, =#r_pc
str r0, [r7]
pop {r4-r7,pc}
.global cpu6502_run
.type cpu6502_run, %function
cpu6502_run:
push {r4-r7,lr}
mov r0, r8
mov r1, r9
mov r2, r10
mov r3, r11
mov r4, r12
push {r0-r4}
_resume
_decode
quit:
mov r12, r0
_suspend
pop {r0-r4}
mov r8, r0
mov r9, r1
mov r10, r2
mov r11, r3
mov r0, r12
mov r12, r4
pop {r4-r7,pc}
// void dump(uint16_t pc);
.type dump, %function
dump:
push {lr}
_suspend
ldr r0, =#r_sp
ldr r1, [r0]
ldr r0, =#r_sr
ldr r2, [r0]
push {r1,r2}
ldr r3, =#r_pc
ldr r0, [r3]
ldr r3, =#r_a
ldr r1, [r3]
ldr r3, =#r_x
ldr r2, [r3]
ldr r3, =#r_y
ldr r3, [r3]
// r0=pc, r1=a, r2=x, r3=y, [sp]=sp, [sp+4]=sr
bl cpu6502_dump
mov r0, sp
adds r0, r0, #8
mov sp, r0
pop {pc}
.section .rodata
op_table:
.long op00
.long op01
.long op02
.long op03
.long op04
.long op05
.long op06
.long op07
.long op08
.long op09
.long op0a
.long op0b
.long op0c
.long op0d
.long op0e
.long op0f
.long op10
.long op11
.long op12
.long op13
.long op14
.long op15
.long op16
.long op17
.long op18
.long op19
.long op1a
.long op1b
.long op1c
.long op1d
.long op1e
.long op1f
.long op20
.long op21
.long op22
.long op23
.long op24
.long op25
.long op26
.long op27
.long op28
.long op29
.long op2a
.long op2b
.long op2c
.long op2d
.long op2e
.long op2f
.long op30
.long op31
.long op32
.long op33
.long op34
.long op35
.long op36
.long op37
.long op38
.long op39
.long op3a
.long op3b
.long op3c
.long op3d
.long op3e
.long op3f
.long op40
.long op41
.long op42
.long op43
.long op44
.long op45
.long op46
.long op47
.long op48
.long op49
.long op4a
.long op4b
.long op4c
.long op4d
.long op4e
.long op4f
.long op50
.long op51
.long op52
.long op53
.long op54
.long op55
.long op56
.long op57
.long op58
.long op59
.long op5a
.long op5b
.long op5c
.long op5d
.long op5e
.long op5f
.long op60
.long op61
.long op62
.long op63
.long op64
.long op65
.long op66
.long op67
.long op68
.long op69
.long op6a
.long op6b
.long op6c
.long op6d
.long op6e
.long op6f
.long op70
.long op71
.long op72
.long op73
.long op74
.long op75
.long op76
.long op77
.long op78
.long op79
.long op7a
.long op7b
.long op7c
.long op7d
.long op7e
.long op7f
.long op80
.long op81
.long op82
.long op83
.long op84
.long op85
.long op86
.long op87
.long op88
.long op89
.long op8a
.long op8b
.long op8c
.long op8d
.long op8e
.long op8f
.long op90
.long op91
.long op92
.long op93
.long op94
.long op95
.long op96
.long op97
.long op98
.long op99
.long op9a
.long op9b
.long op9c
.long op9d
.long op9e
.long op9f
.long opa0
.long opa1
.long opa2
.long opa3
.long opa4
.long opa5
.long opa6
.long opa7
.long opa8
.long opa9
.long opaa
.long opab
.long opac
.long opad
.long opae
.long opaf
.long opb0
.long opb1
.long opb2
.long opb3
.long opb4
.long opb5
.long opb6
.long opb7
.long opb8
.long opb9
.long opba
.long opbb
.long opbc
.long opbd
.long opbe
.long opbf
.long opc0
.long opc1
.long opc2
.long opc3
.long opc4
.long opc5
.long opc6
.long opc7
.long opc8
.long opc9
.long opca
.long opcb
.long opcc
.long opcd
.long opce
.long opcf
.long opd0
.long opd1
.long opd2
.long opd3
.long opd4
.long opd5
.long opd6
.long opd7
.long opd8
.long opd9
.long opda
.long opdb
.long opdc
.long opdd
.long opde
.long opdf
.long ope0
.long ope1
.long ope2
.long ope3
.long ope4
.long ope5
.long ope6
.long ope7
.long ope8
.long ope9
.long opea
.long opeb
.long opec
.long oped
.long opee
.long opef
.long opf0
.long opf1
.long opf2
.long opf3
.long opf4
.long opf5
.long opf6
.long opf7
.long opf8
.long opf9
.long opfa
.long opfb
.long opfc
.long opfd
.long opfe
.long opff
.bss
.global cpu6502_pc
cpu6502_pc:
r_pc: .long 0
r_a: .long 0
r_x: .long 0
r_y: .long 0
r_sp: .long 0
r_sr: .long 0
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