Applerm-II/6502.S

1420 lines
16 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
#define T0 r4
#define T1 r5
#define PC r6
#define SR r7
#define RA r8
#define RX r9
#define RY r10
#define SP r11
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#define ADDR r12
#define FLAG_N (1 << 7)
#define FLAG_V (1 << 6)
#define FLAG_D (1 << 3)
#define FLAG_I (1 << 2)
#define FLAG_Z (1 << 1)
#define FLAG_C (1 << 0)
.macro _ldb
bl cpu6502_load
.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
bl cpu6502_store
.endm
.macro _stw
mov T0, r0
mov T1, r1
bl cpu6502_store
adds r0, T0, #1
lsrs r1, T1, #8
bl cpu6502_store
.endm
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.macro _pushb reg
mov r0, SP
mov r1, \reg
_stb
mov r0, SP
subs r0, r0, #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
mov r1, \reg
_stb
mov r0, SP
subs r0, r0, #2
mov SP, r0
.endm
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.macro _popb
mov r0, SP
adds r0, r0, #1
mov SP, r0
_ldb
.endm
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.macro _popw
mov T0, SP
adds r0, T0, #1
_ldb
mov T1, r0
adds r0, T0, #2
mov SP, r0
_ldb
lsls r0, r0, #8
adds r0, r0, T1
.endm
.macro _decode
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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
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.macro _fromAbsb
adds PC, PC, #1
mov r0, PC
_ldw
mov ADDR, r0
_ldb
.endm
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.macro _fromAbsoluteIndexed reg
adds PC, PC, #1
mov r0, PC
_ldw
add r0, r0, \reg
mov ADDR, r0
_ldb
.endm
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.macro _fromImmb
adds PC, PC, #1
mov r0, PC
_ldb
.endm
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.macro _fromIndexedIndirect
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_fromImmb
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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
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mov ADDR, r0
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_ldb
.endm
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.macro _fromIndirectIndex
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_fromImmb
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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
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.macro _fromReg reg
mov r0, \reg
.endm
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.macro _fromZero
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_fromImmb
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mov ADDR, r0
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_ldb
.endm
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.macro _fromZeroIndex reg
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_fromImmb
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add r0, r0, \reg
uxtb r0, r0
mov ADDR, r0
_ldb
.endm
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.macro _toAddr
mov r0, ADDR
mov r1, T0
_stb
.endm
.macro _toReg reg
mov \reg, T0
.endm
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.macro _toZero
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_fromImmb
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mov r1, T0
_stb
.endm
.macro __cl flag
movs T0, #\flag
bics SR, SR, T0
.endm
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.macro __se flag
movs T0, #\flag
orrs SR, SR, T0
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.endm
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.macro _flag_nz
__cl (FLAG_N | FLAG_Z)
movs r0, r0
bne 1f
__se FLAG_Z
1:
movs r1, #0x80
tst r0, r1
beq 1f
__se FLAG_N
1:
.endm
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.macro _clx flag
__cl \flag
adds PC, PC, #1
.endm
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.macro _sex flag
__se \flag
adds PC, PC, #1
.endm
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.macro _asl
__cl (FLAG_N | FLAG_Z | FLAG_C)
movs r1, #0x80
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:
adds PC, PC, #1
.endm
.macro _bit
__cl (FLAG_N | FLAG_Z | FLAG_V)
mov r1, RA
ands r0, r1, r0
bne 1f
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__se FLAG_Z
1:
movs r1, #0x80
tst r0, r1
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beq 1f
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__se FLAG_N
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1:
movs r1, #0x40
tst r0, r1
beq 1f
__se FLAG_V
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1:
.endm
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.macro _bxx
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_fromImmb
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sxtb r0, r0
add PC, PC, r0
.endm
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.macro _jmp
mov PC, r0
.endm
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.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
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.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, #0x80
tst r0, r1
beq 1f
__se FLAG_N
1:
adds PC, PC, #1
.endm
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.macro _nop
adds PC, PC, #1
.endm
.macro _rol
movs r2, #FLAG_C
ands r2, SR, r2
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__cl (FLAG_N | FLAG_Z | FLAG_C)
movs r1, #0x80
tst r0, r1
beq 1f
__se FLAG_C
1:
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lsls r0, r0, #1
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uxtb r0, r0
adds r0, r0, r2
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bne 1f
__se FLAG_Z
1:
tst r0, r1
beq 1f
__se FLAG_N
1:
adds PC, PC, #1
.endm
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.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, #0x80
tst r0, r1
beq 1f
__se FLAG_N
1:
adds PC, PC, #1
.endm
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.macro _rti
_popb
mov SR, r0
_popw
mov PC, r0
.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
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// NOP
op02:
op03:
op04:
op07:
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op0b:
op0c:
op0f:
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op12:
op13:
op14:
op17:
op1a:
op1b:
op1c:
op1f:
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op22:
op23:
op27:
op2b:
op2f:
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op32:
op33:
op34:
op37:
op3a:
op3b:
op3c:
op3f:
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op42:
op43:
op44:
op47:
op4b:
op4f:
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_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
_decode
op01: // ORA - (Indirect, X)
_fromIndexedIndirect
_lop orrs
_decode
op05: // ORA - Zero Page
_fromZero
_lop orrs
_decode
op06: // ASL - Zero Page
_fromZero
_asl
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_toAddr
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_decode
op08: // PHP
_pushb SR
adds PC, PC, #1
_decode
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op09: // ORA - Immediate
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_fromImmb
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_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
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op10: // BPL (N==0)
movs r0, #FLAG_N
tst SR, r0
bne 1f
_bxx
1:
_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
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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
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_pushw T0
adds r0, PC, #1
_ldw
mov PC, r0
_decode
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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
adds PC, PC, #1
_decode
op29: // AND - Immediate
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_fromImmb
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_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
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op30: // BMI (N==1)
movs r0, #FLAG_N
tst SR, r0
beq 1f
_bxx
1:
_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
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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
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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:
b quit
op51:
b quit
op52:
b quit
op53:
b quit
op54:
b quit
op55:
b quit
op56:
b quit
op57:
b quit
op58: // CLI
_clx FLAG_I
_decode
op59:
b quit
op5a:
b quit
op5b:
b quit
op5c:
b quit
op5d:
b quit
op5e:
b quit
op5f:
b quit
op60:
b quit
op61:
b quit
op62:
b quit
op63:
b quit
op64:
b quit
op65:
b quit
op66:
b quit
op67:
b quit
op68:
b quit
op69:
b quit
op6a:
b quit
op6b:
b quit
op6c:
b quit
op6d:
b quit
op6e:
b quit
op6f:
b quit
op70:
b quit
op71:
b quit
op72:
b quit
op73:
b quit
op74:
b quit
op75:
b quit
op76:
b quit
op77:
b quit
op78: // SEI
_sex FLAG_I
_decode
op79:
b quit
op7a:
b quit
op7b:
b quit
op7c:
b quit
op7d:
b quit
op7e:
b quit
op7f:
b quit
op80:
b quit
op81:
b quit
op82:
b quit
op83:
b quit
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op84: // STY - Zero Page
mov T0, RY
_toZero
_decode
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op85:
b quit
op86:
b quit
op87:
b quit
op88:
b quit
op89:
b quit
op8a:
b quit
op8b:
b quit
op8c:
b quit
op8d:
b quit
op8e:
b quit
op8f:
b quit
op90:
b quit
op91:
b quit
op92:
b quit
op93:
b quit
op94:
b quit
op95:
b quit
op96:
b quit
op97:
b quit
op98:
b quit
op99:
b quit
op9a:
b quit
op9b:
b quit
op9c:
b quit
op9d:
b quit
op9e:
b quit
op9f:
b quit
opa0: // LDY - Immediate
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_fromImmb
_ld RY
_decode
opa1:
b quit
opa2: // LDX - Immediate
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_fromImmb
_ld RX
_decode
opa3:
b quit
opa4:
b quit
opa5:
b quit
opa6:
b quit
opa7:
b quit
opa8:
b quit
opa9: // LDA - Immediate
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_fromImmb
_ld RA
_decode
opaa:
b quit
opab:
b quit
opac:
b quit
opad:
b quit
opae:
b quit
opaf:
b quit
opb0:
b quit
opb1:
b quit
opb2:
b quit
opb3:
b quit
opb4:
b quit
opb5:
b quit
opb6:
b quit
opb7:
b quit
opb8: // CLV
_clx FLAG_V
_decode
opb9:
b quit
opba:
b quit
opbb:
b quit
opbc:
b quit
opbd:
b quit
opbe:
b quit
opbf:
b quit
opc0:
b quit
opc1:
b quit
opc2:
b quit
opc3:
b quit
opc4:
b quit
opc5:
b quit
opc6:
b quit
opc7:
b quit
opc8:
b quit
opc9:
b quit
opca:
b quit
opcb:
b quit
opcc:
b quit
opcd:
b quit
opce:
b quit
opcf:
b quit
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opd0: // BNE (Z==0)
movs r0, #FLAG_Z
tst SR, r0
bne 1f
_bxx
1:
_decode
opd1:
b quit
opd2:
b quit
opd3:
b quit
opd4:
b quit
opd5:
b quit
opd6:
b quit
opd7:
b quit
opd8: // CLD
_clx FLAG_D
_decode
opd9:
b quit
opda:
b quit
opdb:
b quit
opdc:
b quit
opdd:
b quit
opde:
b quit
opdf:
b quit
ope0:
b quit
ope1:
b quit
ope2:
b quit
ope3:
b quit
ope4:
b quit
ope5:
b quit
ope6:
b quit
ope7:
b quit
ope8:
b quit
ope9:
b quit
opea:
b quit
opeb:
b quit
opec:
b quit
oped:
b quit
opee:
b quit
opef:
b quit
opf0:
b quit
opf1:
b quit
opf2:
b quit
opf3:
b quit
opf4:
b quit
opf5:
b quit
opf6:
b quit
opf7:
b quit
opf8: // SED
_sex FLAG_D
_decode
opf9:
b quit
opfa:
b quit
opfb:
b quit
opfc:
b quit
opfd:
b quit
opfe:
b quit
opff:
b quit
.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
r_pc: .long 0
r_a: .long 0
r_x: .long 0
r_y: .long 0
r_sp: .long 0
r_sr: .long 0