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|
;This code is copyrighted by Empty Head (c)1997, but
;you can use it without any charge in your own programs
;use it on your own risk ;)
;DEBUG ;if it is active it is possible to trace through 6502 memory
;SERVER ;if conrol server is active
;C_BUGGING ;debug in C - logical, isn't it ? :)
ifd DEBUG
bra START
endc
OPT P=68040,O+,W-
ifnd DEBUG
xref _GETBYTE ;procedures for A800 bytes
xref _PUTBYTE
xref _Escape
xref _break_addr
xref _tisk
xdef _regPC
xdef _regA
xdef _regP ;/* Processor Status Byte (Partial) */
xdef _regS
xdef _regX
xdef _regY
xref _memory
xref _attrib
xdef _IRQ
xdef _NMI
xdef _RTI
xdef _GO
xdef _CPUGET
xdef _INIT
xdef _OPMODE_TABLE
ifd C_BUGGING
xref _CEKEJ
xdef _ADRESA
xdef _AIRQ
endc
endc
regA
_regA ds.b 1 ;d0 -A
regX
_regX ds.b 1 ;d1 -X
regY
_regY ds.b 1 ;d2 -Y
regS
_regS ds.b 1 ;stack
regPC
_regPC ds.w 1 ;a4 PC
regP
VBDIFLAG ;same as regP
_regP ds.b 1 ; -CCR
IRQ ;I have to reserve it there because other it is 32-bit number (in GCC)
_IRQ ds.b 1
even
CD equr a6 ;cycles counter down
_pointer equr a1
memory_pointer equr a5
attrib_pointer equr a3
stack_pointer equr a2
PC6502 equr a4
ZFLAG equr d5 ;we used it straight in shifting, because it is faster than move again
;I mean rol, ror, asl, asr, lsr, lsl
NFLAG equr d3 ;
CCR6502 equr d4 ;only carry is usable (Extended on 68000)
A equr d0
X equr d1
Y equr d2 ;$206 ;d2
;d6 contains usually adress where we are working
;d7 contains is a working register
LoHi macro ;change order of lo and hi byte in d6
ror.w #8,d7
endm
; ==========================================================
; Emulated Registers and Flags are kept local to this module
; ==========================================================
;#define UPDATE_GLOBAL_REGS regPC=PC;regS=S;regA=A;regX=X;regY=Y
UPDATE_GLOBAL_REGS macro
sub.l memory_pointer,PC6502
sub.l memory_pointer,stack_pointer
lea -$101(stack_pointer),stack_pointer
move.w stack_pointer,d6
lea _regP(pc),a1
move.w PC6502,-(a1) ;_PC6502
move.b d6,-(a1) ;regS
move.b Y,-(a1) ;regY
move.b X,-(a1) ;regX
move.b A,-(a1) ;regA
endm
;#define UPDATE_LOCAL_REGS PC=regPC;S=regS;A=regA;X=regX;Y=regY
UPDATE_LOCAL_REGS macro
lea _regA(pc),a1
clr.w A
move.b (a1)+,A ;A register
clr.w X
move.b (a1)+,X ;X
clr.w Y
move.b (a1)+,Y ;Y
clr.l d7
move.b (a1)+,d7 ;stack regS
lea $101(memory_pointer),stack_pointer
add.l d7,stack_pointer
move.w (a1)+,d7
move.l memory_pointer,PC6502
add.l d7,PC6502
endm
;~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
;~~~~~ WAKE UP PROCESSOR IN DEBUG MODE ~
;~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ifd DEBUG
START: bsr _INIT ;make from OPCODE TABLE & MODE TABLE - OPMODE TABLE
clr.l -(a7)
move.w #32,-(a7)
trap #1
addq.l #6,a7
move.l d0,-(a7)
lea _memory,memory_pointer
clr.b IRQ ;no interrupt
move.b #$20,regP ;unused bit is always 1
move.b #$ff,regS ;set up stack to the star
move.w (memory_pointer,$fffc.l),d7 ;start addres
;move.w #$0020,d7
LoHi
move.w d7,regPC
UPDATE_LOCAL_REGS
clr.l d0
;move.l #3560,d0
;lea TEST,a0
move.l $4ba,-(a7)
ANOTHER:
move.l #27360,-(a7) ;one screen
bsr _GO
addq.l #4,a7
;move.l (a7)+,a0
;move.l d7,(a0)+
sub.l #1,AAA
bne.s ANOTHER
move.l $4ba.l,d7
sub.l (a7)+,d7
move.l d7,$200.w
move.w #32,-(a7)
trap #1
addq.l #6,a7
illegal
clr.w -(a7)
trap #1
endc
section data
AAA: dc.l 50
section text
_INIT:
movem.l a2/a3/d2,-(a7) ;copy opcyc table
lea OPMODE_TABLE,a1
;move.l a1,d2 ;we need to start on a word adress
;add.l #4,d2
;and.l #$fffffc,d2
;move.l d2,a1
;lea OPCODE_TABLE,a1 ;3rd case of jump (mode, get, then this command)
lea MODE_TABLE2,a0 ;1st case of jump (mode)
lea MODE_TABLE1,a3 ;2nd case of jump (jump after mode (in put case it is instruction, if get then we will call get byte routine)
move.w #255,d0
COPY
move.l (a0)+,(a1)+ ;base jump (instruction or mode)
move.l (a3)+,d2 ;jump
cmp.l #opcode_81,d2
beq.s WRITE_WRITE
cmp.l #opcode_84,d2
beq.s WRITE_WRITE
cmp.l #opcode_85,d2
beq.s WRITE_WRITE
cmp.l #opcode_86,d2
beq.s WRITE_WRITE
cmp.l #opcode_8c,d2
beq.s WRITE_WRITE
cmp.l #opcode_8d,d2
beq.s WRITE_WRITE
cmp.l #opcode_8e,d2
beq.s WRITE_WRITE
cmp.l #opcode_91,d2
beq.s WRITE_WRITE
cmp.l #opcode_94,d2
beq.s WRITE_WRITE
cmp.l #opcode_95,d2
beq.s WRITE_WRITE
cmp.l #opcode_96,d2
beq.s WRITE_WRITE
cmp.l #opcode_99,d2
beq.s WRITE_WRITE
cmp.l #opcode_9d,d2
beq.s WRITE_WRITE
;sub.l #JUMP_CODE+2,d2
move.l d2,(a1)+ ;write jump down
;addq.l #2,a1
bra.s NEXT
WRITE_WRITE:
;sub.l #JUMP_CODE+2,d2
bset #31,d2
move.l d2,(a1)+ ;write jump down
;addq.l #2,a1
NEXT: dbf d0,COPY
movem.l (a7)+,a2/a3/d2
rts
;these are bit in MC68000 CCR register
NB68 equ 3
EB68 equ 4 ;used as a carry in 6502 emulation
ZB68 equ 2
OB68 equ 1
CB68 equ 0
N_FLAG equ $80 ;tested in ZN flag in the same way as usual on 6502
N_FLAGB equ 7
V_FLAG equ $40
V_FLAGB equ 6
G_FLAG equ $20
G_FLAGB equ $5
B_FLAG equ $10
B_FLAGB equ 4
D_FLAG equ $08
D_FLAGB equ 3
I_FLAG equ $04
I_FLAGB equ 2
Z_FLAG equ $02
Z_FLAGB equ 1
C_FLAG equ $01
C_FLAGB equ 0
;void CPU_GetStatus (void) - assembler (CPU_ST.S)
;void CPU_PutStatus (void) - assembler (CPU_ST.S)
;void CPU_Reset (void) - C (CPU_ST.C)
;void SetRAM (int addr1, int addr2) - C (CPU_ST.C)
;void SetROM (int addr1, int addr2) - C (CPU_ST.C)
;void SetHARDWARE (int addr1, int addr2) - C (CPU_ST.C)
;void NMI (void) - C (CPU_ST.C)
;void GO (int cycles); - assembler (CPU_ST.S)
SetI macro
bset #I_FLAGB,_regP
endm
ClrI macro
bclr #I_FLAGB,_regP
endm
SetB macro
bset #B_FLAGB,_regP
endm
ClrD macro
bclr #D_FLAGB,_regP
endm
SetD macro
bset #D_FLAGB,_regP
endm
;#define SetN regP|=N_FLAG
;#define ClrN regP&=(~N_FLAG)
;#define SetV regP|=V_FLAG
;#define ClrV regP&=(~V_FLAG)
;#define SetB regP|=B_FLAG
;#define ClrB regP&=(~B_FLAG)
;#define SetD regP|=D_FLAG
;#define ClrD regP&=(~D_FLAG)
;#define SetI regP|=I_FLAG
;#define ClrI regP&=(~I_FLAG)
;#define SetZ regP|=Z_FLAG
;#define ClrZ regP&=(~Z_FLAG)
;#define SetC regP|=C_FLAG
;#define ClrC regP&=(~C_FLAG)
;extern UBYTE memory[65536];
;extern int IRQ;
;#endif
goto macro
bra \1
endm
;static char *rcsid = "$Id: cpu_m68k.s,v 1.2 1998/02/21 15:02:46 david Exp $";
;static UBYTE N; /* bit7 zero (0) or bit 7 non-zero (1) */
;static UBYTE Z; /* zero (0) or non-zero (1) */
;static UBYTE V;
;static UBYTE C; /* zero (0) or one(1) */
RAM equ 0
ROM equ 1
HARDWARE equ 2
;/*
; * The following array is used for 6502 instruction profiling
; */
;int count[256];
;UBYTE memory[65536];
;int IRQ;
;static UBYTE attrib[65536];
;#define GetByte(addr) ((attrib[addr] == HARDWARE) ? Atari800_GetByte(addr) : memory[addr])
;#define PutByte(addr,byte) if (attrib[addr] == RAM) memory[addr] = byte; else if (attrib[addr] == HARDWARE) if (Atari800_PutByte(addr,byte)) break;
;/*
; ===============================================================
; Z flag: This actually contains the result of an operation which
; would modify the Z flag. The value is tested for
; equality by the BEQ and BNE instruction.
; ===============================================================
;*/
; Bit : 76543210
; CCR6502: ***XNZVC
; _RegP : NV*BDIZC
ConvertSTATUS_RegP macro
move.b _regP,d6 ;put flag VBDI into d6
bset #C_FLAGB,d6 ;put there carry flag
btst #EB68,CCR6502
bne.s .SETC\@
bclr #C_FLAGB,d6
.SETC\@ bset #N_FLAGB,d6 ;put there Negative flag
tst.b NFLAG
bmi.s .SETN\@
bclr #N_FLAGB,d6
.SETN\@ bset #Z_FLAGB,d6 ;put there zero flag
tst.b ZFLAG
beq.s .SETZ\@ ;is there beware! reverse compare is ok
bclr #Z_FLAGB,d6
.SETZ\@
endm
ConvertRegP_STATUS macro
move.b _regP,d6
moveq #-1,CCR6502
btst #C_FLAGB,d6
bne.s .SETC\@
clr.w CCR6502
.SETC\@ clr.b ZFLAG
btst #Z_FLAGB,d6
bne.s .SETZ\@ ;reverse is ok
not.b ZFLAG
.SETZ\@ clr.b NFLAG
btst #N_FLAGB,d6
beq.s .SETN\@
not.b NFLAG
.SETN\@
endm
CPU_GetStatus macro
ConvertSTATUS_RegP
move.b d6,_regP
endm
CPU_PutStatus macro
ConvertRegP_STATUS
endm
PHP macro
ConvertSTATUS_RegP
move.b d6,-(stack_pointer)
endm
PLP macro
move.b (stack_pointer)+,_regP
ConvertRegP_STATUS
endm
;#define AND(t_data) data = t_data; Z = N = A &= data;
;#define CMP(t_data) data = t_data; Z = N = A - data; C = (A >= data)
;#define CPX(t_data) data = t_data; Z = N = X - data; C = (X >= data);
;#define CPY(t_data) data = t_data; Z = N = Y - data; C = (Y >= data);
;#define EOR(t_data) data = t_data; Z = N = A ^= data;
;#define LDA(data) Z = N = A = data;
;#define LDX(data) Z = N = X = data;
;#define LDY(data) Z = N = Y = data;
;#define ORA(t_data) data = t_data; Z = N = A |= data
;#define PHP data = (N & 0x80); \
; data |= V ? 0x40 : 0; \
; data |= (regP & 0x3c); \
; data |= (Z == 0) ? 0x02 : 0; \
; data |= C; \
; memory[0x0100 + S--] = data;
;
;#define PLP data = memory[0x0100 + ++S]; \
; N = (data & 0x80); \
; V = (data & 0x40) ? 1 : 0; \
; Z = (data & 0x02) ? 0 : 1; \
; C = (data & 0x01); \
; regP = (data & 0x3c) | 0x20;
;
CPUGET:
_CPUGET:
ConvertSTATUS_RegP
move.b d6,_regP
rts
NMI:
_NMI:
movem.l d0-d7/a0-a6,-(a7)
lea _memory,memory_pointer
move.w _regPC,d6 ;we will put adress on stack of 6502
ror.w #8,d6
clr.l d7 ;find stack in memory
move.b _regS,d7
move.l d7,stack_pointer
add.l memory_pointer,stack_pointer
lea $101(stack_pointer),stack_pointer
move.w d6,-(stack_pointer) ;put back adress onto stack
move.b _regP,-(stack_pointer) ;put P onto stack YEAAAH!
SetI
;put regPC & Stack pointer adress on its place
move.w (memory_pointer,$fffa.l),d7
LoHi
move.w d7,_regPC
lea -$101(stack_pointer),stack_pointer
move.l stack_pointer,d7 ;put stack
sub.l memory_pointer,d7
move.b d7,_regS
movem.l (a7)+,d0-d7/a0-a6
ifd SERVER
move.w #1,WAIT
endc
rts
;UBYTE S = regS;
;UBYTE data;
;memory[0x0100 + S--] = regPC >> 8;
;memory[0x0100 + S--] = regPC & 0xff;
;PHP;
;SetI;
;regPC = (memory[0xfffb] << 8) | memory[0xfffa];
;regS = S;
;/*
; ==============================================================
; The first switch statement is used to determine the addressing
; mode, while the second switch implements the opcode. When I
; have more confidence that these are working correctly they
; will be combined into a single switch statement. At the
; moment changes can be made very easily.
; ==============================================================
;*/
section data
CYCLES:
dc.w 7, 2, 0, 8, 3, 3, 5, 5, 3, 2, 2, 2, 4, 4, 6, 6
dc.w 2, 5, 0, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7
dc.w 6, 6, 0, 8, 3, 3, 5, 5, 4, 2, 2, 2, 4, 4, 6, 6
dc.w 2, 5, 0, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7
dc.w 6, 6, 0, 8, 3, 3, 7, 5, 3, 2, 2, 2, 3, 4, 6, 6
dc.w 2, 5, 0, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 0, 7
dc.w 6, 6, 0, 8, 3, 3, 5, 5, 4, 2, 2, 2, 5, 4, 6, 6
dc.w 2, 5, 0, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7
dc.w 2, 6, 2, 6, 3, 3, 3, 3, 2, 2, 2, 2, 4, 4, 4, 4
dc.w 2, 6, 0, 6, 4, 4, 4, 4, 2, 5, 2, 5, 5, 5, 5, 5
dc.w 2, 6, 2, 6, 3, 3, 3, 3, 2, 2, 2, 2, 4, 4, 4, 4
dc.w 2, 5, 0, 5, 4, 4, 4, 4, 2, 4, 2, 4, 4, 4, 4, 4
dc.w 2, 6, 2, 8, 3, 3, 5, 5, 2, 2, 2, 2, 4, 4, 6, 6
dc.w 2, 5, 0, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7
dc.w 2, 6, 2, 8, 3, 3, 5, 5, 2, 2, 2, 2, 4, 4, 6, 6
dc.w 2, 5, 0, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7
MODE_TABLE1:
;when we will call instruction straight, this table is used
;when we want to get byte, this table contains addr to GET BYTE routine
;when we want to put byte, this table contains addr to own command
;when we want to put and get byte (rol, ror, inc etc.), this routine is the same as in the case GET BYTE
;if the instruction take byte straight from command, this routine contains addr to own comman as well
dc.l opcode_00, opcode_01, opcode_02, opcode_03
; brk ora illegal illegal
dc.l opcode_04,opcode_05,opcode_06, opcode_07
; nop ora asl nop
dc.l opcode_08,opcode_09,opcode_0a,opcode_0b
; php ora asla illegal
dc.l opcode_0c,opcode_0d,opcode_0e,opcode_0f
; nop 3 ora asl illegal
dc.l opcode_10,opcode_11, opcode_12, opcode_13
; bpl ora illegal illegal
dc.l opcode_14,opcode_15, opcode_16, opcode_17
; nop ora asl illegal
dc.l opcode_18,opcode_19, opcode_1a, opcode_1b
; clc ora nop illegal
dc.l opcode_1c,opcode_1d, opcode_1e, opcode_1f
; nop ora asl illegal
dc.l opcode_20,opcode_21,opcode_22, opcode_23
; jsr and illegal illegal
dc.l opcode_24,opcode_25,opcode_26,opcode_27
; bit and rol illegal
dc.l opcode_28, opcode_29, opcode_2a, opcode_2b
; plp and rolA illegal
dc.l opcode_2c, opcode_2d, opcode_2e, opcode_2f
; bit and rol illegal
dc.l opcode_30, opcode_31, opcode_32, opcode_33
; bmi and illegal illegal
dc.l opcode_34, opcode_35, opcode_36, opcode_37
; nop and rol illegal
dc.l opcode_38, opcode_39, opcode_3a, opcode_3b
; sec and nop illegal
dc.l opcode_3c, opcode_3d, opcode_3e, opcode_3f
; nop and rol illegal
dc.l opcode_40, opcode_41, opcode_42, opcode_43
; rti eor illegal illegal
dc.l opcode_44, opcode_45, opcode_46, opcode_47
; nop eor lsr illegal
dc.l opcode_48, opcode_49, opcode_4a, opcode_4b
; pha eor lsrA illegal
dc.l opcode_4c, opcode_4d, opcode_4e, opcode_4f
; jmp eor lsr illegal
dc.l opcode_50, opcode_51, opcode_52, opcode_53
; bvc eor illegal illegal
dc.l opcode_54, opcode_55, opcode_56, opcode_57
; nop eor lsr illegal
dc.l opcode_58, opcode_59, opcode_5a, opcode_5b
; cli eor nop illegal
dc.l opcode_5c, opcode_5d, opcode_5e, opcode_5f
; nop eor lsr illegal
dc.l opcode_60, opcode_61, opcode_62, opcode_63
; rts adc illegal illegal
dc.l opcode_64, opcode_65, opcode_66, opcode_67
; nop adc ror illegal
dc.l opcode_68, opcode_69,opcode_6a,opcode_6b
; pla adc rorA illegal
dc.l opcode_6c, opcode_6d, opcode_6e, opcode_6f
; jmp (abcd) adc ror illegal
dc.l opcode_70, opcode_71, opcode_72, opcode_73
; bvs adc illegal illegal
dc.l opcode_74, opcode_75, opcode_76, opcode_77
; nop adc ror illegal
dc.l opcode_78, opcode_79, opcode_7a, opcode_7b
; SEI adc illegal illegal
dc.l opcode_7c, opcode_7d, opcode_7e, opcode_7f
; nop adc ror illegal
dc.l opcode_80, opcode_81, opcode_82, opcode_83
; nop sta nop illegal
dc.l opcode_84, opcode_85, opcode_86,opcode_87
; sty sta stx illegal
dc.l opcode_88, opcode_89, opcode_8a, opcode_8b
; dey nop txa illegal
dc.l opcode_8c, opcode_8d, opcode_8e, opcode_8f
; sty sta stx illegal
dc.l opcode_90, opcode_91, opcode_92, opcode_93
; bcc sta illegal illegal
dc.l opcode_94, opcode_95, opcode_96, opcode_97
; sty sta stx illegal
dc.l opcode_98, opcode_99, opcode_9a, opcode_9b
; tya sta txs illegal
dc.l opcode_9c, opcode_9d, opcode_9e, opcode_9f
; illegal sta ilegal illegal
dc.l opcode_a0, opcode_a1, opcode_a2, opcode_a3
; ldy lda ldx lax
dc.l opcode_a4, opcode_a5, opcode_a6, opcode_a7
; ldy lda ldx lax
dc.l opcode_a8, opcode_a9, opcode_aa, opcode_ab
; tay lda tax illegal
dc.l opcode_ac, opcode_ad, opcode_ae, opcode_af
; ldy lda ldx lax
dc.l opcode_b0, opcode_b1, opcode_b2, opcode_b3
; bcs lda illegal lax
dc.l opcode_b4, opcode_b5, opcode_b6, opcode_b7
; ldy lda ldx lax
dc.l opcode_b8, opcode_b9, opcode_ba, opcode_bb
; clv lda tsx illegal
dc.l opcode_bc, opcode_bd, opcode_be, opcode_bf
; ldy lda ldx lax
dc.l opcode_c0, opcode_c1, opcode_c2, opcode_c3
; cpy cmp nop illegal
dc.l opcode_c4, opcode_c5, opcode_c6, opcode_c7
; cpy cmp dec illegal
dc.l opcode_c8, opcode_c9, opcode_ca, opcode_cb
; iny cmp dex illegal
dc.l opcode_cc, opcode_cd, opcode_ce, opcode_cf
; cpy cmp dec illegal
dc.l opcode_d0, opcode_d1, opcode_d2, opcode_d3
; bne cmp escrts illegal
dc.l opcode_d4, opcode_d5, opcode_d6, opcode_d7
; nop cmp dec illegal
dc.l opcode_d8, opcode_d9, opcode_da, opcode_db
; cld cmp nop illegal
dc.l opcode_dc, opcode_dd, opcode_de, opcode_df
; nop cmp dec illegal
dc.l opcode_e0, opcode_e1, opcode_e2, opcode_e3
; cpx sbc nop nop
dc.l opcode_e4, opcode_e5, opcode_e6, opcode_e7
; cpx sbc inc illegal
dc.l opcode_e8, opcode_e9,opcode_ea, opcode_eb
; inx sbc nop illegal
dc.l opcode_ec, opcode_ed, opcode_ee, opcode_ef
; cpx sbc inc illegal
dc.l opcode_f0, opcode_f1, opcode_f2, opcode_f3
; beq sbc esc#ab illegal
dc.l opcode_f4, opcode_f5, opcode_f6, opcode_f7
; nop sbc inc illegal
dc.l opcode_f8, opcode_f9, opcode_fa, opcode_fb
; sed sbc nop illegal
dc.l opcode_fc, opcode_fd, opcode_fe, opcode_ff
; nop sbc inc esc#ab
MODE_TABLE2:
dc.l opcode_00, INDIRECT_X, opcode_02, opcode_03
; brk ora illegal illegal
dc.l opcode_04, ZPAGE, ZPAGE, opcode_07
; nop ora asl nop
dc.l opcode_08, DIRECT, opcode_0a, opcode_0b
; php ora asla illegal
dc.l opcode_0c, ABSOLUTE, ABSOLUTE, opcode_0f
; nop 3 ora asl illegal
dc.l opcode_10, INDIRECT_Y, opcode_12, opcode_13
; bpl ora illegal illegal
dc.l opcode_14, ZPAGE_X, ZPAGE_X, opcode_17
; nop ora asl illegal
dc.l opcode_18, ABSOLUTE_Y, opcode_1a, opcode_1b
; clc ora nop illegal
dc.l opcode_1c, ABSOLUTE_X,ABSOLUTE_X, opcode_1f
; nop ora asl illegal
dc.l opcode_20, INDIRECT_X,opcode_22, opcode_23
; jsr and illegal illegal
dc.l ZPAGE, ZPAGE, ZPAGE, opcode_27
; bit and rol illegal
dc.l opcode_28, DIRECT, opcode_2a, opcode_2b
; plp and rolA illegal
dc.l ABSOLUTE, ABSOLUTE, ABSOLUTE, opcode_2f
; bit and rol illegal
dc.l opcode_30, INDIRECT_Y, opcode_32, opcode_33
; bmi and illegal illegal
dc.l opcode_34, ZPAGE_X, ZPAGE_X, opcode_37
; nop and rol illegal
dc.l opcode_38, ABSOLUTE_Y, opcode_3a, opcode_3b
; sec and nop illegal
dc.l opcode_3c, ABSOLUTE_X, ABSOLUTE_X, opcode_3f
; nop and rol illegal
dc.l opcode_40, INDIRECT_X, opcode_42, opcode_43
; rti eor illegal illegal
dc.l opcode_44, ZPAGE, ZPAGE, opcode_47
; nop eor lsr illegal
dc.l opcode_48, DIRECT, opcode_4a, opcode_4b
; pha eor lsrA illegal
dc.l opcode_4c, ABSOLUTE, ABSOLUTE, opcode_4f
; jmp eor lsr illegal
dc.l opcode_50, INDIRECT_Y, opcode_52, opcode_53
; bvc eor illegal illegal
dc.l opcode_54, ZPAGE_X, ZPAGE_X, opcode_57
; nop eor lsr illegal
dc.l opcode_58, ABSOLUTE_Y, opcode_5a, opcode_5b
; cli eor nop illegal
dc.l opcode_5c, ABSOLUTE_X, ABSOLUTE_X, opcode_5f
; nop eor lsr illegal
dc.l opcode_60, INDIRECT_X, opcode_62, opcode_63
; rts adc illegal illegal
dc.l opcode_64, ZPAGE, ZPAGE, opcode_67
; nop adc ror illegal
dc.l opcode_68, DIRECT, opcode_6a, opcode_6b
; pla adc rorA illegal
dc.l opcode_6c, ABSOLUTE, ABSOLUTE, opcode_6f
; jmp (abcd) adc ror illegal
dc.l opcode_70, INDIRECT_Y, opcode_72, opcode_73
; bvs adc illegal illegal
dc.l opcode_74, ZPAGE_X, ZPAGE_X, opcode_77
; nop adc ror illegal
dc.l opcode_78, ABSOLUTE_Y, opcode_7a, opcode_7b
; SEI adc illegal illegal
dc.l opcode_7c, ABSOLUTE_X, ABSOLUTE_X, opcode_7f
; nop adc ror illegal
dc.l opcode_80, INDIRECT_X, opcode_82, opcode_83
; nop sta nop illegal
dc.l ZPAGE, ZPAGE, ZPAGE, opcode_87
; sty sta stx illegal
dc.l opcode_88, opcode_89, opcode_8a, opcode_8b
; dey nop txa illegal
dc.l ABSOLUTE, ABSOLUTE, ABSOLUTE, opcode_8f
; sty sta stx illegal
dc.l opcode_90, INDIRECT_Y, opcode_92, opcode_93
; bcc sta illegal illegal
dc.l ZPAGE_X, ZPAGE_X, ZPAGE_Y, opcode_97
; sty sta stx illegal
dc.l opcode_98, ABSOLUTE_Y, opcode_9a, opcode_9b
; tya sta txs illegal
dc.l opcode_9c, ABSOLUTE_X, opcode_9e, opcode_9f
; illegal sta ilegal illegal
dc.l DIRECT, INDIRECT_X, DIRECT, INDIRECT_X
; ldy lda ldx lax
dc.l ZPAGE, ZPAGE, ZPAGE, ZPAGE
; ldy lda ldx lax
dc.l opcode_a8, DIRECT, opcode_aa, opcode_ab
; tay lda tax illegal
dc.l ABSOLUTE, ABSOLUTE, ABSOLUTE, ABSOLUTE
; ldy lda ldx lax
dc.l opcode_b0, INDIRECT_Y, opcode_b2, INDIRECT_Y
; bcs lda illegal lax
dc.l ZPAGE_X, ZPAGE_X, ZPAGE_Y, ZPAGE_Y
; ldy lda ldx lax
dc.l opcode_b8, ABSOLUTE_Y, opcode_ba, opcode_bb
; clv lda tsx illegal
dc.l ABSOLUTE_X, ABSOLUTE_X, ABSOLUTE_Y, ABSOLUTE_Y
; ldy lda ldx lax
dc.l DIRECT, INDIRECT_X, opcode_c2, opcode_c3
; cpy cmp nop illegal
dc.l ZPAGE, ZPAGE, ZPAGE, opcode_c7
; cpy cmp dec illegal
dc.l opcode_c8, DIRECT, opcode_ca, opcode_cb
; iny cmp dex illegal
dc.l ABSOLUTE, ABSOLUTE, ABSOLUTE, opcode_cf
; cpy cmp dec illegal
dc.l opcode_d0, INDIRECT_Y, opcode_d2, opcode_d3
; bne cmp escrts illegal
dc.l opcode_d4, ZPAGE_X, ZPAGE_X, opcode_d7
; nop cmp dec illegal
dc.l opcode_d8, ABSOLUTE_Y, opcode_da, opcode_db
; cld cmp nop illegal
dc.l opcode_dc, ABSOLUTE_X, ABSOLUTE_X, opcode_df
; nop cmp dec illegal
dc.l DIRECT, INDIRECT_X, opcode_e2, opcode_e3
; cpx sbc nop nop
dc.l ZPAGE, ZPAGE, ZPAGE, opcode_e7
; cpx sbc inc illegal
dc.l opcode_e8, DIRECT, opcode_ea, opcode_eb
; inx sbc nop illegal
dc.l ABSOLUTE, ABSOLUTE, ABSOLUTE, opcode_ef
; cpx sbc inc illegal
dc.l opcode_f0, INDIRECT_Y, opcode_f2, opcode_f3
; beq sbc esc#ab illegal
dc.l opcode_f4, ZPAGE_X, ZPAGE_X, opcode_f7
; nop sbc inc illegal
dc.l opcode_f8, ABSOLUTE_Y, opcode_fa, opcode_fb
; sed sbc nop illegal
dc.l opcode_fc, ABSOLUTE_X, ABSOLUTE_X, opcode_ff
; nop sbc inc esc#ab
section text
_GO: ;cycles (d0)
; UWORD PC;
; UBYTE S;
; UBYTE A;
; UBYTE X;
; UBYTE Y;
;
; UWORD addr;
; UBYTE data;
;/*
; This used to be in the main loop but has been removed to improve
; execution speed. It does not seem to have any adverse effect on
; the emulation for two reasons:-
;
; 1. NMI's will can only be raised in atari_custom.c - there is
; no way an NMI can be generated whilst in this routine.
;
; 2. The timing of the IRQs are not that critical.
;*/
movem.l d0-d7/a0-a6,-(a7)
move.w 66(a7),CD ;write how much cycles (should be 6)
lea _memory,memory_pointer
UPDATE_LOCAL_REGS
ConvertRegP_STATUS
lea OPMODE_TABLE,a0
lea _attrib,attrib_pointer
tst.b _IRQ
beq GET_FIRST_INSTRUCTION
move.b _regP,d6
and.b #I_FLAG,d6 ;is interrupt active
bne GET_FIRST_INSTRUCTION ;yes, no other interrupt
_AIRQ: move.w _regPC,d7 ;UAAAA :) ;write back addr
LoHi
move.w d7,-(stack_pointer)
move.b _regP,-(stack_pointer)
;PHP
SetI
clr.l d7
move.w (memory_pointer,$fffe.l),d7
LoHi
move.l d7,PC6502
add.l memory_pointer,PC6502
clr.b _IRQ ;clear interrupt.....
ifd SERVER
move.w #-1,WAIT
endc
bra GET_FIRST_INSTRUCTION
END_OF_CYCLE:
;move.l (a7)+,a1
ConvertSTATUS_RegP
move.b d6,_regP
UPDATE_GLOBAL_REGS
movem.l (a7)+,d0-d7/a0-a6
rts
ADRESA: dc.l 1
;UPDATE_LOCAL_REGS
;if (IRQ)
; {
; if (!(regP & I_FLAG))
; {
; UWORD retadr = PC;
; memory[0x0100 + S--] = retadr >> 8;
; memory[0x0100 + S--] = retadr & 0xff;
; PHP;
; SetI;
; PC = (memory[0xffff] << 8) | memory[0xfffe];
; IRQ = 0;
; }
; }
;/*
; =====================================
; Extract Address if Required by Opcode
; =====================================
;*/
;d6 contains final value for use in program
ZPAGE_X
move.l 4(a0,d7.l*8),d6
move.b (PC6502)+,d7
add.b X,d7
subq.w #2,CD
bra.s TEST
ZPAGE_Y
move.l 4(a0,d7.l*8),d6
move.b (PC6502)+,d7
add.b Y,d7
subq.w #2,CD
bra.s TEST
ABSOLUTE_Y
move.l 4(a0,d7.l*8),d6
move.w (PC6502)+,d7
ror.w #8,d7
add.w Y,d7
subq.w #2,CD
bra.s TEST
INDIRECT_Y
move.l 4(a0,d7.l*8),d6
move.b (PC6502)+,d7
move.w (memory_pointer,d7.l),d7
ror.w #8,d7 ;swap bytes
add.w Y,d7
subq.w #4,CD
bra.s TEST
ABSOLUTE_X
move.l 4(a0,d7.l*8),d6
move.w (PC6502)+,d7
ror.w #8,d7
add.w X,d7 ;add x to
subq.w #2,CD
bra.s TEST
INDIRECT_X
move.l 4(a0,d7.l*8),d6
move.b (PC6502)+,d7
add.b X,d7
move.w (memory_pointer,d7.l),d7
ror.w #8,d7
subq.w #4,CD
bra.s TEST
ABSOLUTE:
move.l 4(a0,d7.l*8),d6
move.w (PC6502)+,d7
ror.w #8,d7 ;d7 contains reversed value
subq.w #2,CD
bra.s TEST
ZPAGE:
move.l 4(a0,d7.l*8),d6
move.b (PC6502)+,d7 ;d6 contains offset
subq.w #1,CD
bra.s TEST
DIRECT:
move.l 4(a0,d7.l*8),a1
move.b (PC6502)+,d6
jmp (a1)
TEST: bclr #31,d6 ;get highest byte away
bne.s JUST_WRITE
move.l d6,a1
GONEBYTE: ;get one byte from memory
tst.b (attrib_pointer,d7.l)
bne.s JGetbyte
GZPAGEBYTE: ;get one byte from zero page
move.b (memory_pointer,d7.l),d6 ;get byte
AFTER_READ:
JUMP_CODE: jmp (a1)
JUST_WRITE: move.l d6,a1
jmp (a1) ;bra.s JUMP_CODE
JGetbyte:
bra A800GETB
PUTONEBYTE_FL:
move.b d6,NFLAG
move.b d6,ZFLAG
PUTONEBYTE: tst.b (attrib_pointer,d7.l)
bne.s .Putbyte
move.b d6,(memory_pointer,d7.l)
goto NEXTCHANGE_WITHOUT
.Putbyte
bra A800PUTB
;#define ABSOLUTE addr=(memory[PC+1]<<8)+memory[PC];PC+=2;
;#define ZPAGE addr=memory[PC++];
;#define ABSOLUTE_X addr=((memory[PC+1]<<8)+memory[PC])+(UWORD)X;PC+=2;
;#define ABSOLUTE_Y addr=((memory[PC+1]<<8)+memory[PC])+(UWORD)Y;PC+=2;
;#define INDIRECT_X addr=(UWORD)memory[PC++]+(UWORD)X;addr=(memory[addr+1]<<8)+memory[addr];
;#define INDIRECT_Y addr=memory[PC++];addr=(memory[addr+1]<<8)+memory[addr]+(UWORD)Y;
;#define ZPAGE_X addr=(memory[PC++]+X)&0xff;
;#define ZPAGE_Y addr=(memory[PC++]+Y)&0xff;
BB
opcode_8d: ;/* STA abcd */
opcode_85: ;/* STA ab */
opcode_81: ;/* STA (ab,x) */
opcode_91: ;/* STA (ab),y */
opcode_95: ;/* STA ab,x */
opcode_99: ;/* STA abcd,y */
opcode_9d: ;/* STA abcd,x */
move.b A,d6
bra.s PUTONEBYTE
opcode_8e: ;/* STX abcd */
opcode_86: ;/* STX ab */
opcode_96: ;/* STX ab,y */
move.b X,d6
bra.s PUTONEBYTE
opcode_8c: ;/* STY abcd */
opcode_84: ;/* STY ab */
opcode_94: ;/* STY ab,x */
move.b Y,d6
bra.s PUTONEBYTE
opcode_e6: ;/* INC ab */
opcode_ee: ;/* INC abcd */
opcode_f6: ;/* INC ab,x */
opcode_fe: ;/* INC abcd,x */
addq.b #2,d6 ;again funny piece of code
opcode_c6: ;/* DEC ab */
opcode_ce: ;/* DEC abcd */
opcode_d6: ;/* DEC ab,x */
opcode_de: ;/* DEC abcd,x */
subq.b #1,d6
bra.s PUTONEBYTE_FL ;put one byte with flags
opcode_0e: ;/* ASL abcd */
opcode_06: ;/* ASL ab */
opcode_16: ;/* ASL ab,x */
opcode_1e: ;/* ASL abcd,x */
clr.w CCR6502
opcode_2e: ;/* ROL abcd */
opcode_36: ;/* ROL ab,x */
opcode_26: ;/* ROL ab */
opcode_3e: ;/* ROL abcd,x */
move.w CCR6502,CCR
addx.b d6,d6 ;left
move.w CCR,CCR6502
bra.s PUTONEBYTE_FL
opcode_46: ;/* LSR ab */
opcode_4e: ;/* LSR abcd */
opcode_56: ;/* LSR ab,x */
opcode_5e: ;/* LSR abcd,x */
clr.w CCR6502
opcode_6e: ;/* ROR abcd */
opcode_66: ;/* ROR ab */
opcode_76: ;/* ROR ab,x */
opcode_7e: ;/* ROR abcd,x */
move.w CCR6502,CCR
roxr.b #1,d6
move.w CCR,CCR6502
bra.s PUTONEBYTE_FL
opcode_a9: ;/* LDA #ab */
opcode_a5: ;/* LDA ab */
opcode_a1: ;/* LDA (ab,x) */
opcode_ad: ;/* LDA abcd */
opcode_b1: ;/* LDA (ab),y */
opcode_b5: ;/* LDA ab,x */
opcode_b9: ;/* LDA abcd,y */
opcode_bd: ;/* LDA abcd,x */
move.b d6,A
bra.s NEXTCHANGE
opcode_a2: ;/* LDX #ab */
opcode_a6: ;/* LDX ab */
opcode_ae: ;/* LDX abcd */
opcode_b6: ;/* LDX ab,y */
opcode_be: ;/* LDX abcd,y */
move.b d6,X
bra.s NEXTCHANGE
opcode_a0: ;/* LDY #ab */
opcode_a4: ;/* LDY ab */
opcode_ac: ;/* LDY abcd */
opcode_b4: ;/* LDY ab,x */
opcode_bc: ;/* LDY abcd,x */
move.b d6,Y
bra.s NEXTCHANGE
opcode_e0: ;/* CPX #ab */
opcode_e4: ;/* CPX ab */
opcode_ec: ;/* CPX abcd */
move.b X,NFLAG
bra.s COMPARE
opcode_c0: ;/* CPY #ab */
opcode_c4: ;/* CPY ab */
opcode_cc: ;/* CPY abcd */
move.b Y,NFLAG
bra.s COMPARE
opcode_c1: ;/* CMP (ab,x) */
opcode_c5: ;/* CMP ab */
opcode_c9: ;/* CMP #ab */
opcode_cd: ;/* CMP abcd */
opcode_d1: ;/* CMP (ab),y */
opcode_d5: ;/* CMP ab,x */
opcode_d9: ;/* CMP abcd,y */
opcode_dd: ;/* CMP abcd,x */
move.b A,NFLAG
COMPARE: sub.b d6,NFLAG
move.w CCR,CCR6502
not.w CCR6502
move.b NFLAG,ZFLAG
bra.s NEXTCHANGE_WITHOUT ;without flags
opcode_29: ;/* AND #ab */
opcode_21: ;/* AND (ab,x) */
opcode_25: ;/* AND ab */
opcode_2d: ;/* AND abcd */
opcode_31: ;/* AND (ab),y */
opcode_35: ;/* AND ab,x */
opcode_39: ;/* AND abcd,y */
opcode_3d: ;/* AND abcd,x */
and.b d6,A
bra.s NEXTCHANGE_A ;change flags as A is set
opcode_49: ;/* EOR #ab */
opcode_41: ;/* EOR (ab,x) */
opcode_45: ;/* EOR ab */
opcode_4d: ;/* EOR abcd */
opcode_51: ;/* EOR (ab),y */
opcode_55: ;/* EOR ab,x */
opcode_59: ;/* EOR abcd,y */
opcode_5d: ;/* EOR abcd,x */
eor.b d6,A
bra.s NEXTCHANGE_A
opcode_09: ;/* ORA #ab */
opcode_01: ;/* ORA (ab,x) */
opcode_05: ;/* ORA ab */
opcode_0d: ;/* ORA abcd */
opcode_11: ;/* ORA (ab),y */
opcode_15: ;/* ORA ab,x */
opcode_19: ;/* ORA abcd,y */
opcode_1d: ;/* ORA abcd,x */
or.b d6,A
;MAIN LOOP , where we are counting cycles and working with other STUFF
NEXTCHANGE_A: move.b A,d6
NEXTCHANGE: move.b d6,ZFLAG
move.b d6,NFLAG
NEXTCHANGE_WITHOUT:
ifd C_BUGGING
tst.w CD
bmi ENDGO ;should be .S
endc
ifd SERVER
UPDATE_GLOBAL_REGS
ConvertSTATUS_RegP
move.b d6,_regP
tst.w WAIT
bne STRAIGHT_GO ;if interrupt is active we won't test and will run until the end of interrupt is reached
lea $400000,a1
.WAIT_FOR_DATA:
cmp.l #$12345678,-16(a1)
bne.s .WAIT_FOR_DATA
move.b _regP,d6
cmp.b -1(a1),d6
bne.s .PRINT_OUT
move.b _regS,d6
cmp.b -2(a1),d6
bne.s .PRINT_OUT
move.b _regA,d6
cmp.b -3(a1),d6
bne.s .PRINT_OUT
move.b _regX,d6
cmp.b -4(a1),d6
bne.s .PRINT_OUT
move.b _regY,d6
cmp.b -5(a1),d6
bne.s .PRINT_OUT
move.w _regPC,d6
cmp.w -8(a1),d6
bne.s .PRINT_OUT
bra CONTINUE
.PRINT_OUT:
movem.l a0-a6,-(a7)
CPU_GetStatus
jsr _tisk /*in atari c*/
CPU_PutStatus
movem.l (a7)+,a0-a6
CONTINUE: lea $400000,a1
move.l #'A800',-16(a1)
STRAIGHT_GO: ;interrupt is active, dont try trace....
UPDATE_LOCAL_REGS
endc
ifd C_BUGGING
move.l PC6502,A1
sub.l a5,a1
cmp.l _CEKEJ,a1
bne.s CONT
_ADRESA: nop
ifd DEBUG
illegal
endc
endc
CONT: ;move.l a1,-(a7)
subq.w #2,CD
tst.w CD
bmi.s ENDGO
GET_FIRST_INSTRUCTION:
****************************************
ifd BREAKING following block of code allows you to enter
move ccr,-(sp) a break address in monitor
move.l PC6502,d7
sub.l memory_pointer,d7
cmp.w _break_addr,d7
bne.s .get_first
move.b #$ff,d7
move (sp)+,ccr
bsr odskoc_si on break monitor is invoked
move ccr,-(sp)
.get_first
move (sp)+,ccr
endc
****************************************
clr.l d7
move.b (PC6502)+,d7
;move.w 4(a0,d7.l*8),d6
JUMPMODE: jmp ([a0,d7.l*8])
ENDGO: bra END_OF_CYCLE ;the end of cycle
opcode_0a: ;/* ASLA */
clr.w CCR6502
opcode_2a: ;/* ROLA */
move.w CCR6502,CCR
addx.b A,A ;rolx #1,A
move.w CCR,CCR6502
bra NEXTCHANGE_A
opcode_4a: ;/* LSRA */
clr.w CCR6502
opcode_6a: ;/* RORA */
move.w CCR6502,CCR
roxr.b #1,A
move.w CCR,CCR6502
bra NEXTCHANGE_A
opcode_90: ;/* BCC */
btst #EB68,CCR6502
beq.s SOLVE
bra.s NOTHING
opcode_b0: ;/* BCS */
btst #EB68,CCR6502
bne.s SOLVE
bra.s NOTHING
opcode_f0: ;/* BEQ */
tst.b ZFLAG
beq.s SOLVE
bra.s NOTHING
opcode_d0: ;/* BNE */
tst.b ZFLAG
beq.s NOTHING
SOLVE:
move.b (PC6502)+,d7
extb.l d7
add.l d7,PC6502
;lea (PC6502,d7.l),PC6502
bra NEXTCHANGE_WITHOUT
NOTHING: addq.l #1,PC6502
bra NEXTCHANGE_WITHOUT
opcode_ca: ;/* DEX */ ;funny code DEX(-2)+1
subq.b #2,X
opcode_e8: ;/* INX */
addq.b #1,X
move.b X,d6
bra NEXTCHANGE
opcode_88: ;/* DEY */ ;funny code (DEY(-2)+1
subq.b #2,Y
opcode_c8: ;/* INY */
addq.b #1,Y
move.b Y,d6
bra NEXTCHANGE
opcode_a8: ;/* TAY */
move.b A,Y
opcode_98: ;/* TYA */
move.b Y,A
bra NEXTCHANGE_A
opcode_aa: ;/* TAX */
move.b A,X
opcode_8a: ;/* TXA */
move.b X,A
bra NEXTCHANGE_A
opcode_20: ;/* JSR abcd */
move.l PC6502,d7 ;current pointer
sub.l memory_pointer,d7
addq.l #1,d7 ;back addres
LoHi ;(it puts result into d6)
move.w d7,-(stack_pointer)
opcode_4c: ;/* JMP abcd */
move.w (PC6502)+,d7
LoHi ;(in d7 adress where we want to jump)
lea (memory_pointer,d7.l),PC6502
;add.l d7,PC6502
subq.w #4,CD
goto NEXTCHANGE_WITHOUT
opcode_60: ;/* RTS */
move.w (stack_pointer)+,d7
LoHi
lea 1(memory_pointer,d7.l),PC6502
;addq.l #1,PC6502
subq.w #4,CD
goto NEXTCHANGE_WITHOUT
opcode_50: ;/* BVC */
btst #V_FLAGB,_regP
beq.s SOLVE
bra.s NOTHING
opcode_70: ;/* BVS */
btst #V_FLAGB,_regP
bne.s SOLVE
bra.s NOTHING
opcode_10: ;/* BPL */
and.b #N_FLAG,NFLAG
beq.s SOLVE
bra.s NOTHING
opcode_30: ;/* BMI */
and.b #N_FLAG,NFLAG
bne.s SOLVE
bra.s NOTHING
opcode_24: ;/* BIT ab */
opcode_2c: ;/* BIT abcd */
move.b d6,NFLAG
btst #V_FLAGB,d6
beq.s .UNSET
bset #V_FLAGB,_regP
move.b A,ZFLAG
and.b NFLAG,ZFLAG
bra NEXTCHANGE_WITHOUT
.UNSET:
bclr #V_FLAGB,_regP
move.b A,ZFLAG
and.b NFLAG,ZFLAG
bra NEXTCHANGE_WITHOUT
opcode_40: ;/* RTI */
_RTI:
PLP
move.w (stack_pointer)+,d7
LoHi
lea (memory_pointer,d7.l),PC6502
subq.w #4,CD
ifd SERVER
clr.w WAIT
endc
goto NEXTCHANGE_WITHOUT
opcode_61: ;/* ADC (ab,x) */
opcode_65: ;/* ADC ab */
opcode_69: ;/* ADC #ab */
opcode_6d: ;/* ADC abcd */
opcode_71: ;/* ADC (ab),y */
opcode_75: ;/* ADC ab,x */
opcode_79: ;/* ADC abcd,y */
opcode_7d: ;/* ADC abcd,x */
adc:
;/* ADC */
; unsigned int temp = src + AC + (IF_CARRY() ? 1 : 0);
; SET_ZERO(temp & 0xff); /* This is not valid in decimal mode */
; if (IF_DECIMAL()) {
; if (((AC & 0xf) + (src & 0xf) + (IF_CARRY() ? 1 : 0)) > 9) temp += 6;
; SET_SIGN(temp);
; SET_OVERFLOW(!((AC ^ src) & 0x80) && ((AC ^ temp) & 0x80));
; if (temp > 0x99) temp += 96;
; SET_CARRY(temp > 0x99);
; } else {
; SET_SIGN(temp);
; SET_OVERFLOW(!((AC ^ src) & 0x80) && ((AC ^ temp) & 0x80));
; SET_CARRY(temp > 0xff);
; }
; AC = ((BYTE) temp);
;addq.l #1,AAAAA
btst #D_FLAGB,_regP
bne.s BDC_ADC
move.w CCR6502,CCR
addx.b d6,A ;data are added with carry (in 68000 Extended bit in this case)
move.w CCR,CCR6502
svs d6
and.b #V_FLAG,d6
* and.b #-V_FLAG,_regP
and.b #~V_FLAG,_regP
or.b d6,_regP
bra NEXTCHANGE_A
;if (!(regP & D_FLAG))
;{
; UWORD temp;
; UWORD t_data;
;t_data = (UWORD)data + (UWORD)C;
;Z = N = temp = (UWORD)A + t_data;
;V = (~(A ^ t_data)) & (Z ^ A) & 0x80; ;cruel construction :((
;C = temp >> 8;
;A = Z;
;}
BDC_ADC:
move.b CCR6502,CCR
ori.b #4,CCR ; set zero flag
abcd d6,A
move.b CCR,CCR6502 ;V flag isn't soluted
bra NEXTCHANGE_A
;else
;{
; int bcd1, bcd2;
; bcd1 = BCDtoDEC[A];
; bcd2 = BCDtoDEC[data];
; bcd1 += bcd2 + C;
; Z = N = DECtoBCD[bcd1];
; V = (Z ^ A) & 0x80;
; C = (bcd1 > 99);
; A = Z;
;}
;goto next;
opcode_e1: ;/* SBC (ab,x) */
opcode_e5: ;/* SBC ab */
opcode_e9: ;/* SBC #ab */
opcode_ed: ;/* SBC abcd */
opcode_f1: ;/* SBC (ab),y */
opcode_f5: ;/* SBC ab,x */
opcode_f9: ;/* SBC abcd,y */
opcode_fd: ;/* SBC abcd,x */
sbc:
;/* SBC */
; unsigned int temp = AC - src - (IF_CARRY() ? 0 : 1);
; SET_SIGN(temp);
; SET_ZERO(temp & 0xff); /* Sign and Zero are invalid in decimal mode */
; SET_OVERFLOW(((AC ^ temp) & 0x80) && ((AC ^ src) & 0x80));
; if (IF_DECIMAL()) {
; if ( ((AC & 0xf) - (IF_CARRY() ? 0 : 1)) < (src & 0xf)) /* EP */ temp -= 6;
; if (temp > 0x99) temp -= 0x60;
; }
; SET_CARRY(temp < 0x100);
; AC = (temp & 0xff);
;addq.l #1,AAAAA
btst #D_FLAGB,_regP
bne.s BDC_SBC
not.w CCR6502 ;change it????
move.w CCR6502,CCR
subx.b d6,A
move.w CCR,CCR6502
svs d6
not.w CCR6502
and.b #V_FLAG,d6
* and.b #-V_FLAG,_regP
and.b #~V_FLAG,_regP
or.b d6,_regP
bra NEXTCHANGE_A
;if (!(regP & D_FLAG))
;{
; UWORD temp;
; UWORD t_data;
;t_data = (UWORD)data + (UWORD)!C;
;temp = (UWORD)A - t_data;
;Z = N = temp & 0xff;
;/*
; * This was the old code that I have been using upto version 0.5.2
; * C = (A < ((UWORD)data + (UWORD)!C)) ? 0 : 1;
; */
; V = (~(A ^ t_data)) & (Z ^ A) & 0x80;
; C = (temp > 255) ? 0 : 1;
; A = Z;
; }
BDC_SBC:
not.w CCR6502 ;change it ?????
move.b CCR6502,CCR
ori.b #4,CCR ; set zero flag
sbcd d6,A
move.b CCR,CCR6502 ;V flag isn't soluted
not.w CCR6502
goto NEXTCHANGE_A
;else
;{
; int bcd1, bcd2;
;
; bcd1 = BCDtoDEC[A];
; bcd2 = BCDtoDEC[data];
; bcd1 = bcd1 - bcd2 - !C;
; if (bcd1 < 0) bcd1 = 100 - (-bcd1);
; Z = N = DECtoBCD[bcd1];
; C = (A < (data + !C)) ? 0 : 1;
; V = (Z ^ A) & 0x80;
; A = Z;
;}
;goto next;
opcode_68: ;/* PLA */
move.b (stack_pointer)+,A
subq.w #1,CD
bra NEXTCHANGE_A
opcode_08: ;/* PHP */
PHP
subq.w #1,CD
bra NEXTCHANGE_WITHOUT
opcode_48: ;/* PHA */
move.b A,-(stack_pointer)
subq.w #1,CD
bra NEXTCHANGE_WITHOUT
opcode_28: ;/* PLP */
PLP
subq.w #1,CD
bra NEXTCHANGE_WITHOUT
opcode_18: ;/* CLC */
clr.w CCR6502
bra NEXTCHANGE_WITHOUT
opcode_38: ;/* SEC */
moveq.w #-1,CCR6502
bra NEXTCHANGE_WITHOUT
opcode_58: ;/* CLI */
ClrI
bra NEXTCHANGE_WITHOUT
opcode_d8: ;/* CLD */
ClrD
bra NEXTCHANGE_WITHOUT
opcode_b8: ;/* CLV */
bclr.b #V_FLAGB,_regP
bra NEXTCHANGE_WITHOUT
opcode_6c: ;/* JMP (abcd) */
move.w (PC6502)+,d7
LoHi
move.w (memory_pointer,d7.l),d7
LoHi
lea (memory_pointer,d7.l),PC6502
subq.w #5,CD
bra NEXTCHANGE_WITHOUT
opcode_78: ;/* SEI */
SetI
bra NEXTCHANGE_WITHOUT
opcode_f8: ;/* SED */
SetD
bra NEXTCHANGE_WITHOUT
opcode_9a: ;/* TXS */
lea (memory_pointer,X.w),stack_pointer
lea $101(stack_pointer),stack_pointer
bra NEXTCHANGE_WITHOUT
opcode_ba: ;/* TSX */
move.l stack_pointer,X
sub.l memory_pointer,X
sub.l #$101,X ;HIHIHI :) 3rd discovered error in last 30 hours....
;this one is because logic of STACK on 6502 4th error in 32 hours :)
move.b X,d6
bra NEXTCHANGE
opcode_0c: ;/* NOP (3 bytes) [unofficial] */
opcode_3c:
opcode_5c:
opcode_7c:
opcode_dc:
opcode_fc:
addq.l #1,PC6502
subq.w #3,CD
opcode_04: ;/* NOP (2 bytes) [unofficial] */
opcode_14:
opcode_1c:
opcode_34:
opcode_44:
opcode_54:
opcode_64:
opcode_74:
opcode_80:
opcode_82:
opcode_89:
opcode_c2:
opcode_d4:
opcode_e2:
opcode_f4:
addq.l #1,PC6502
subq.w #3,CD
opcode_1a: ;/* NOP (1 byte) [unofficial] */
opcode_3a:
opcode_5a:
opcode_7a:
opcode_da:
opcode_fa:
opcode_ea: ;/* NOP */ ;oficial
goto NEXTCHANGE_WITHOUT
opcode_d2: ;/* ESCRTS #ab (JAM) */
move.b (PC6502)+,d7
UPDATE_GLOBAL_REGS
movem.l a0-a6,-(a7)
CPU_GetStatus
move.l d7,-(a7)
jsr _Escape /*in atari c*/
addq.l #4,a7
CPU_PutStatus
movem.l (a7)+,a0-a6
UPDATE_LOCAL_REGS
move.w (stack_pointer)+,d7
LoHi
lea (memory_pointer,d7.l),PC6502
addq.l #1,PC6502
bra GET_FIRST_INSTRUCTION
opcode_f2: ;/* ESC #ab (JAM) */
opcode_ff: ;/* ESC #ab */
move.b (PC6502)+,d7
UPDATE_GLOBAL_REGS
movem.l a0-a6,-(a7)
CPU_GetStatus
move.l d7,-(a7)
jsr _Escape
addq.l #4,a7
CPU_PutStatus
movem.l (a7)+,a0-a6
UPDATE_LOCAL_REGS
bra GET_FIRST_INSTRUCTION
opcode_a3: ;/* LAX (ind,x) [unofficial] */
;INDIRECT_X
;GetByte d7
move.b d7,A
move.b d7,X
move.b A,NFLAG
move.b A,ZFLAG
bra NEXTCHANGE_WITHOUT
opcode_a7: ;/* LAX zpage [unofficial] */
;ZPAGE
;GetByte d7
move.b d7,A
move.b d7,X
move.b A,NFLAG
move.b A,ZFLAG
bra NEXTCHANGE_WITHOUT
opcode_af: ;/* LAX absolute [unofficial] */
;ABSOLUTE
;GetByte d7
move.b d7,X
move.b d7,A
move.b A,NFLAG
move.b A,ZFLAG
bra NEXTCHANGE_WITHOUT
opcode_b3: ;/* LAX (ind),y [unofficial] */
;INDIRECT_Y
;GetByte d7
move.b d7,A
move.b d7,X
move.b A,NFLAG
move.b A,ZFLAG
bra NEXTCHANGE_WITHOUT
opcode_b7: ;/* LAX zpage,y [unofficial] */
;ZPAGE_Y
;GetByte d7
move.b d7,A
move.b d7,X
move.b A,NFLAG
move.b A,ZFLAG
bra NEXTCHANGE_WITHOUT
opcode_bf: ;/* LAX absolute,y [unofficial] */
;ABSOLUTE_Y
;GetByte d7
move.b d7,A
move.b d7,X
move.b X,ZFLAG
move.b X,NFLAG
bra NEXTCHANGE_WITHOUT
opcode_02:
opcode_03:
opcode_07:
opcode_0b:
opcode_0f:
opcode_12:
opcode_13:
opcode_17:
opcode_1b:
opcode_1f:
opcode_22:
opcode_23:
opcode_27:
opcode_2b:
opcode_2f:
opcode_32:
opcode_33:
opcode_37:
opcode_3b:
opcode_3f:
opcode_42:
opcode_43:
opcode_47:
opcode_4b:
opcode_4f:
opcode_52:
opcode_53:
opcode_57:
opcode_5b:
opcode_5f:
opcode_62:
opcode_63:
opcode_67:
opcode_6b:
opcode_6f:
opcode_72:
opcode_73:
opcode_77:
opcode_7b:
opcode_7f:
opcode_83:
opcode_87:
opcode_8b:
opcode_8f:
opcode_92:
opcode_93:
opcode_97:
opcode_9b:
opcode_9c:
opcode_9e:
opcode_9f:
opcode_ab:
opcode_b2:
opcode_bb:
opcode_c3:
opcode_c7:
opcode_cb:
opcode_cf:
opcode_d3:
opcode_d7:
opcode_db:
opcode_df:
opcode_e3:
opcode_e7:
opcode_eb:
opcode_ef:
opcode_f3:
opcode_f7:
opcode_fb:
;pea text(pc)
;move.w #9,-(a7)
;trap #1
;addq.l #1,ILEGALY
;illegal
bra NEXTCHANGE_WITHOUT
ILEGALY: dc.l 0
text: dc.b 'NEJAKA CHYBA TY BLBE'
even
UPDATE_GLOBAL_REGS
;printf ("*** Invalid Opcode %02x at address %04x\n",
; memory[PC-1], PC-1);
;ncycles = 0;
;break;
opcode_00: ;/* BRK */
btst #I_FLAGB,_regP
bne NEXTCHANGE_WITHOUT
move.l PC6502,d7
sub.l memory_pointer,d7
addq.w #1,d7
LoHi
move.w d7,-(stack_pointer)
SetB
PHP
SetI
move.w (memory_pointer,$fffe.l),d7
LoHi
move.l d7,PC6502
add.l memory_pointer,PC6502
subq.w #5,CD
bra NEXTCHANGE_WITHOUT
A800GETB:
cmp.b #1,(attrib_pointer,d7.l)
beq.s .READ_FROM_ROM
movem.l a0/a1/a6/d0/d1,-(a7)
move.l d7,-(a7)
jsr _GETBYTE
move.w d0,d6 ;put stack onto right place
addq.l #4,a7
movem.l (a7)+,a0/a1/a6/d0/d1
bra AFTER_READ
.READ_FROM_ROM:
move.b (memory_pointer,d7.l),d6
bra AFTER_READ
ifd DEBUG
_GETBYTE: move.b (memory_pointer,d7.l),d6
rts
endc
; I used to be really stupid about stacking in C :))
; I believed that I have to push onto stack every time I call
; C function all registers, Fortunately I don't have to, d0-d1 and a0-a1 is enough
A800PUTB:
cmp.b #1,(attrib_pointer,d7.l)
beq.s .DONT_WRITE_TO_ROM
move.l a0,-(a7)
move.w d0,-(a7)
move.w d1,-(a7)
move.w a6,-(a7)
;movem.l a0/a6/d0/d1,-(a7)
clr.l -(a7)
move.b d6,3(a7) ;byte
move.l d7,-(a7) ;adress
jsr _PUTBYTE
move.w d0,d6 ;put value onto right place
addq.l #8,a7
;movem.l (a7)+,a0/a6/d0/d1
move.w (a7)+,a6
move.w (a7)+,d1
move.w (a7)+,d0
move.l (a7)+,a0
tst.w d6
bne ENDGO
bra NEXTCHANGE_WITHOUT
.DONT_WRITE_TO_ROM:
bra NEXTCHANGE_WITHOUT
ifd DEBUG
_PUTBYTE: move.b d6,(memory_pointer,d7.l)
endc
odskoc_si:
UPDATE_GLOBAL_REGS
movem.l a0-a6,-(a7)
CPU_GetStatus
move.l d7,-(a7)
jsr _Escape
addq.l #4,a7
CPU_PutStatus
movem.l (a7)+,a0-a6
UPDATE_LOCAL_REGS
rts
ifd DEBUG
_CEKEJ: dc.l 1
endc
EE: dc.w 0
WAIT: dc.w 0
section bss
_OPMODE_TABLE:
ds.w 1
OPMODE_TABLE: ds.l 514 (2*256 long words)+2 as a reserve
ifnd DEBUG
LE: ds.l 1
STACKALL: ds.l 16
endc
ifd DEBUG
section data
;VBDIFLAG: dc.w 1 ;information about CCR bits V B D I
dc.l 0
dc.l 0 ;
mem6502: ;dc.l MEMORY
;ds.w 1
memory:
_memory:
ds.b 40960
incbin H:\ATARI800\ATARIBAS.ROM ;load basic
incbin H:\ATARI800\ATARIXL.ROM ;load Atari XL
ds.b 8192
dc.b $a9,50,$69,90,$e9,40,$20,$4c,00,20
dc.b $a9,$00,$a2,0,$a0,0
;lda #0, ldx #0, ldy #0
dc.b $a5,$06,$ae,$1,$1,$bc,2,2
;lda $06 ldx $0101 ldy $0202,x
dc.b $a1,02,$a6,2,$b4,2
;lda (2,x) ldx 2 ldy 2,x
dc.b $81,0,$8e,01,01,$94,22
; sta (0,x) stx $0101 sty 22,y
dc.b $e6,10,$6e,05,05,$e0,10
; INC 10, ROR 0505 CPX #10
dc.b $4c,0,$20
;PL: ds.b 65536-(PL-memory)
attrib:
_attrib: dcb.b $A000,RAM
dcb.b $2000,ROM
dcb.b $1000,HARDWARE
dcb.b $3000,ROM
;dc.b ROM
;dc.b ROM
;dc.b ROM
;dcb.b 16383,RAM
;65536,RAM ;set all the memory as RAM
section bss
TEST2: ds.l 20000
section text
_Escape: rts
endc
section text
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