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opcodes1.asm
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opcodes1.asm
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;*******************************************************************************
; Include: OPCODES1
; Version: 1.20
; Written: July 15, 1990
; Updated: Friday, August 12, 1994 7:52 pm
; Author : Tony G. Papadimitriou
; Purpose: This is an include file with half the opcode routines used by
; the MC6809E.ASM program, an enhanced version of the MC6809E
; emulator program originally written in Turbo Pascal. Because
; it is completely written in Assembly language there should be
; a dramatic speed improvement over the Pascal version.
; Note: SYNC instruction is currently not implemented
; 220129 : Removed redundant JMP instruction by reversing previous conditional jump
;*******************************************************************************
proc mcERROR ; special routine to handle invalid ops
mov ax,130 ; invalid opcode error
call Errors
ret
endp mcERROR
;*******************************************************************************
proc mcNEG
mov al,[OpCode]
shr al,4 ; MSN -> LSN
cmp al,4 ; check it for accumulators
je @@AccA
cmp al,5
je @@AccB
jmp short @@Next
@@AccA: neg [A]
jmp short @@flags
@@AccB: neg [B]
jmp short @@flags
@@Next: call GetEffAddr
neg [byte es:si]
@@flags: pushf ; first clear affected flags
and [CC],11110000b
popf
jno @@1 ; is it the overflow case?
SOverflow
@@1: jnz @@2 ; is it the zero case?
SZero
@@2: jnc @@3 ; is it the carry case?
SCarry
@@3: jns @@exit ; is it the negative case?
SNegative
@@exit: ret
endp mcNEG
;*******************************************************************************
proc mcCOM
mov al,[OpCode]
shr al,4 ; MSN -> LSN
cmp al,4 ; check it for accumulators
je @@AccA
cmp al,5
je @@AccB
jmp short @@Next
@@AccA: not [A]
jmp short @@flags
@@AccB: not [B]
jmp short @@flags
@@Next: call GetEffAddr
not [byte es:si]
@@flags: pushf ; first clear affected flags
and [CC],11110000b
popf
jnz @@1 ; is it the zero case?
SZero
@@1: jns @@exit ; is it the negative case?
SNegative
@@exit: ret
endp mcCOM
;*******************************************************************************
proc mcLSR
mov al,[OpCode]
shr al,4 ; MSN -> LSN
cmp al,4 ; check it for accumulators
je @@AccA
cmp al,5
je @@AccB
jmp short @@Next
@@AccA: shr [A],1
jmp short @@flags
@@AccB: shr [B],1
jmp short @@flags
@@Next: call GetEffAddr
shr [byte es:si],1
@@flags: pushf ; first clear affected flags
and [CC],11110010b
popf
jnz @@1 ; is it the zero case?
SZero
@@1: jnc @@exit ; is it the Carry case?
SCarry
@@exit: ret
endp mcLSR
;*******************************************************************************
proc mcROR
mov al,[OpCode]
shr al,4 ; MSN -> LSN
cmp al,4 ; check it for accumulators
je @@AccA
cmp al,5
je @@AccB
jmp short @@Next
@@AccA: ror [A],1
jmp short @@flags
@@AccB: ror [B],1
jmp short @@flags
@@Next: call GetEffAddr
ror [byte es:si],1
@@flags: pushf ; first clear affected flags
and [CC],11110010b
popf
jnz @@1 ; is it the zero case?
SZero
@@1: jns @@2 ; is it the negative case?
SNegative
@@2: jnc @@exit ; is it the Carry case?
SCarry
@@exit: ret
endp mcROR
;*******************************************************************************
proc mcASR
mov al,[OpCode]
shr al,4 ; MSN -> LSN
cmp al,4 ; check it for accumulators
je @@AccA
cmp al,5
je @@AccB
jmp short @@Next
@@AccA: sar [A],1
jmp short @@flags
@@AccB: sar [B],1
jmp short @@flags
@@Next: call GetEffAddr
sar [byte es:si],1
@@flags: pushf ; first clear affected flags
and [CC],11110010b
popf
jnz @@1 ; is it the zero case?
SZero
@@1: jns @@2 ; is it the negative case?
SNegative
@@2: jnc @@exit ; is it the Carry case?
SCarry
@@exit: ret
endp mcASR
;*******************************************************************************
proc mcASL
mov al,[OpCode]
shr al,4 ; MSN -> LSN
cmp al,4 ; check it for accumulators
je @@AccA
cmp al,5
je @@AccB
jmp short @@Next
@@AccA: sal [A],1
jmp short @@flags
@@AccB: sal [B],1
jmp short @@flags
@@Next: call GetEffAddr
sal [byte es:si],1
@@flags: pushf ; first clear affected flags
and [CC],11110000b
popf
jnz @@1 ; is it the zero case?
SZero
@@1: jns @@2 ; is it the negative case?
SNegative
@@2: jno @@3 ; is it the overflow case?
SOverflow
@@3: jnc @@exit ; is it the Carry case?
SCarry
@@exit: ret
endp mcASL
;*******************************************************************************
proc mcROL
mov al,[OpCode]
shr al,4 ; MSN -> LSN
cmp al,4 ; check it for accumulators
je @@AccA
cmp al,5
je @@AccB
jmp short @@Next
@@AccA: rol [A],1
jmp short @@flags
@@AccB: rol [B],1
jmp short @@flags
@@Next: call GetEffAddr
rol [byte es:si],1
@@flags: pushf ; first clear affected flags
and [CC],11110000b
popf
jnz @@1 ; is it the zero case?
SZero
@@1: jns @@2 ; is it the negative case?
SNegative
@@2: jno @@3 ; is it the overflow case?
SOverflow
@@3: jnc @@exit ; is it the Carry case?
SCarry
@@exit: ret
endp mcROL
;*******************************************************************************
proc mcDEC
mov al,[OpCode]
shr al,4 ; MSN -> LSN
cmp al,4 ; check it for accumulators
je @@AccA
cmp al,5
je @@AccB
jmp short @@Next
@@AccA: dec [A]
jmp short @@flags
@@AccB: dec [B]
jmp short @@flags
@@Next: call GetEffAddr
dec [byte es:si]
@@flags: pushf ; first clear affected flags
and [CC],11110001b
popf
jnz @@1 ; is it the zero case?
SZero
@@1: jns @@2 ; is it the negative case?
SNegative
@@2: jno @@exit ; is it the overflow case?
SOverflow
@@exit: ret
endp mcDEC
;*******************************************************************************
proc mcINC
mov al,[OpCode]
shr al,4 ; MSN -> LSN
cmp al,4 ; check it for accumulators
je @@AccA
cmp al,5
je @@AccB
jmp short @@Next
@@AccA: inc [A]
jmp short @@flags
@@AccB: inc [B]
jmp short @@flags
@@Next: call GetEffAddr
inc [byte es:si]
@@flags: pushf ; first clear affected flags
and [CC],11110001b
popf
jnz @@1 ; is it the zero case?
SZero
@@1: jns @@2 ; is it the negative case?
SNegative
@@2: jno @@exit ; is it the overflow case?
SOverflow
@@exit: ret
endp mcINC
;*******************************************************************************
proc mcTST
mov al,[OpCode]
shr al,4 ; MSN -> LSN
cmp al,4 ; check it for accumulators
je @@AccA
cmp al,5
je @@AccB
jmp short @@Next
@@AccA: test [A],0FFh
jmp short @@flags
@@AccB: test [B],0FFh
jmp short @@flags
@@Next: call GetEffAddr
test [byte es:si],0FFh
@@flags: pushf ; first clear affected flags
and [CC],11110001b
popf
jnz @@1 ; is it the zero case?
SZero
@@1: jns @@exit ; is it the negative case?
SNegative
@@exit: ret
endp mcTST
;*******************************************************************************
proc mcJMP
call GetEffAddr
mov [PC],si
ret
endp mcJMP
;*******************************************************************************
proc mcCLR
mov al,[OpCode]
shr al,4 ; MSN -> LSN
cmp al,4 ; check it for accumulators
je @@AccA
cmp al,5
je @@AccB
jmp short @@Next
@@AccA: mov [A],0
jmp short @@flags
@@AccB: mov [B],0
jmp short @@flags
@@Next: call GetEffAddr
mov [byte es:si],0
@@flags: pushf ; first clear affected flags
and [CC],11110000b
popf
@@exit: ret
endp mcCLR
;*******************************************************************************
proc mcNOP
ret
endp mcNOP
;*******************************************************************************
proc mcSYNC ; not implemented at this time
ret
endp mcSYNC
;*******************************************************************************
proc mcDAA
mov al,[A]
daa
mov [A],al
pushf
and [CC],11110010b
popf
jns @@1
SNegative
@@1: jnz @@2
SZero
@@2: jnc @@exit
SCarry
@@exit: ret
endp mcDAA
;*******************************************************************************
proc mcORCC
mov si,[PC]
GetByte
inc [PC]
or [CC],al
ret
endp mcORCC
;*******************************************************************************
proc mcANDCC
mov si,[PC]
GetByte
inc [PC]
and [CC],al
ret
endp mcANDCC
;*******************************************************************************
proc mcSEX
mov al,[B]
cbw
mov [D],ax
CNegative
CZero
jns @@1
SNegative
@@1: jnz @@exit
SZero
@@exit: ret
endp mcSEX
;*******************************************************************************
; General purpose procedure (see EXG and TFR instructions)
proc GetRegister ; get the value of the register in AL/AX
cmp al,0 ; is it D?
je @@D
cmp al,1 ; is it X?
je @@X
cmp al,2 ; is it Y?
je @@Y
cmp al,3 ; is it U?
je @@U
cmp al,4 ; is it S?
je @@S
cmp al,5 ; is it PC?
je @@PC
cmp al,8 ; is it A?
je @@A
cmp al,9 ; is it B?
je @@B
cmp al,0Ah ; is it CC?
je @@CC
cmp al,0Bh ; is it DP?
je @@DP
jmp short @@exit ; otherwise, undefined register, exit
; 16-bit registers
@@D: mov ax,[D]
jmp short @@exit
@@X: mov ax,[X]
jmp short @@exit
@@Y: mov ax,[Y]
jmp short @@exit
@@U: mov ax,[U]
jmp short @@exit
@@S: mov ax,[S]
jmp short @@exit
@@PC: mov ax,[PC]
jmp short @@exit
; 8-bit registers
@@A: mov al,[A]
jmp short @@exit
@@B: mov al,[B]
jmp short @@exit
@@CC: mov al,[CC]
jmp short @@exit
@@DP: mov al,[DPR]
@@exit: ret
endp GetRegister
;*******************************************************************************
; Purpose: General purpose procedure (see EXG and TFR instructions)
proc PutRegister ; save the value of BL/BX in the register
cmp al,0 ; is it D?
je @@D
cmp al,1 ; is it X?
je @@X
cmp al,2 ; is it Y?
je @@Y
cmp al,3 ; is it U?
je @@U
cmp al,4 ; is it S?
je @@S
cmp al,5 ; is it PC?
je @@PC
cmp al,8 ; is it A?
je @@A
cmp al,9 ; is it B?
je @@B
cmp al,0Ah ; is it CC?
je @@CC
cmp al,0Bh ; is it DP?
je @@DP
jmp short @@exit ; otherwise, undefined register, exit
; 16-bit registers
@@D: mov [D],bx
jmp short @@exit
@@X: mov [X],bx
jmp short @@exit
@@Y: mov [Y],bx
jmp short @@exit
@@U: mov [U],bx
jmp short @@exit
@@S: mov [S],bx
jmp short @@exit
@@PC: mov [PC],bx
jmp short @@exit
; 8-bit registers
@@A: mov [A],bl
jmp short @@exit
@@B: mov [B],bl
jmp short @@exit
@@CC: mov [CC],bl
jmp short @@exit
@@DP: mov [DPR],bl
@@exit: ret
endp PutRegister
;*******************************************************************************
proc mcEXG
mov si,[PC]
GetByte
and al,10001000b ; are they both the same size?
cmp al,10001000b
je @@8bit
cmp al,00000000b
jne @@exit ; cannot transfer different sizes
GetByte ; 16bit case
shr al,4 ; figure out the first register
call GetRegister ; in AX
mov bx,ax ; and save it in BX
GetByte
and al,0Fh ; figure out the second register
call GetRegister ; in AX
xchg ax,bx ; swap the two registers
mov dx,ax ; save AX in DX
GetByte
shr al,4 ; figure out the first register
call PutRegister ; BX
GetByte ; figure out the second register
and al,0Fh
mov bx,dx ; get saved AX
call PutRegister ; BX
jmp short @@exit
@@8bit: GetByte
shr al,4 ; figure out the first register
call GetRegister ; in AL
mov bl,al ; and save it in BL
GetByte
and al,0Fh ; figure out the second register
call GetRegister ; in AL
xchg al,bl ; swap the two registers
mov dl,al ; save AL in DL
GetByte
shr al,4 ; figure out the first register
call PutRegister ; BL
GetByte ; figure out the second register
and al,0Fh
mov bl,dl ; get saved AL
call PutRegister ; BL
@@exit: inc [PC]
ret
endp mcEXG
;*******************************************************************************
proc mcTFR
mov si,[PC]
GetByte
and al,10001000b ; are they both the same size?
cmp al,10001000b
je @@8bit
cmp al,00000000b
jne @@exit ; cannot transfer different sizes
GetByte ; 16bit case
shr al,4 ; figure out the first register
call GetRegister ; in AX
mov bx,ax ; move it to BX
GetByte ; figure out the second register
and al,0Fh
call PutRegister ; BX
jmp short @@exit
@@8bit: GetByte
shr al,4 ; figure out the first register
call GetRegister ; in AL
mov bl,al ; move it to BL
GetByte ; figure out the second register
and al,0Fh
call PutRegister ; BL
@@exit: inc [PC]
ret
endp mcTFR
;*******************************************************************************
proc mcBRA
call GetEffAddr
cmp [OpCode],16h ; is it a long or short branch?
je @@16bit
GetByte
inc [PC]
cbw
jmp short @@exit
@@16bit: GetWord
inc [PC]
inc [PC]
@@exit: add [PC],ax
ret
endp mcBRA
;*******************************************************************************
proc mcBRN
mov al,[Paged] ; is it a long or short branch?
cmp al,10h ; PAGE2?
je @@16bit
inc [PC]
jmp short @@exit
@@16bit: inc [PC]
inc [PC]
@@exit: ret
endp mcBRN
;*******************************************************************************
proc mcBHI
call GetEffAddr
mov al,[Paged] ; is it a long or short branch?
cmp al,10h ; PAGE2?
je @@16bit
GetByte
inc [PC]
cbw
jmp short @@done
@@16bit: GetWord
inc [PC]
inc [PC]
@@done: mov bl,[CC]
and bl,CarryMask+ZeroMask
jnz @@exit
add [PC],ax
@@exit: ret
endp mcBHI
;*******************************************************************************
proc mcBLS
call GetEffAddr
mov al,[Paged] ; is it a long or short branch?
cmp al,10h ; PAGE2?
je @@16bit
GetByte
inc [PC]
cbw
jmp short @@done
@@16bit: GetWord
inc [PC]
inc [PC]
@@done: mov bl,[CC]
and bl,CarryMask+ZeroMask
jz @@exit
add [PC],ax
@@exit: ret
endp mcBLS
;*******************************************************************************
proc mcBHS
call GetEffAddr
mov al,[Paged] ; is it a long or short branch?
cmp al,10h ; PAGE2?
je @@16bit
GetByte
inc [PC]
cbw
jmp short @@done
@@16bit: GetWord
inc [PC]
inc [PC]
@@done: test [CC],CarryMask
jnz @@exit
add [PC],ax
@@exit: ret
endp mcBHS
;*******************************************************************************
proc mcBLO
call GetEffAddr
mov al,[Paged] ; is it a long or short branch?
cmp al,10h ; PAGE2?
je @@16bit
GetByte
inc [PC]
cbw
jmp short @@done
@@16bit: GetWord
inc [PC]
inc [PC]
@@done: test [CC],CarryMask
jz @@exit
add [PC],ax
@@exit: ret
endp mcBLO
;*******************************************************************************
proc mcBNE
call GetEffAddr
mov al,[Paged] ; is it a long or short branch?
cmp al,10h ; PAGE2?
je @@16bit
GetByte
inc [PC]
cbw
jmp short @@done
@@16bit: GetWord
inc [PC]
inc [PC]
@@done: test [CC],ZeroMask
jnz @@exit
add [PC],ax
@@exit: ret
endp mcBNE
;*******************************************************************************
proc mcBEQ
call GetEffAddr
mov al,[Paged] ; is it a long or short branch?
cmp al,10h ; PAGE2?
je @@16bit
GetByte
inc [PC]
cbw
jmp short @@done
@@16bit: GetWord
inc [PC]
inc [PC]
@@done: test [CC],ZeroMask
jz @@exit
add [PC],ax
@@exit: ret
endp mcBEQ
;*******************************************************************************
proc mcBVC
call GetEffAddr
mov al,[Paged] ; is it a long or short branch?
cmp al,10h ; PAGE2?
je @@16bit
GetByte
inc [PC]
cbw
jmp short @@done
@@16bit: GetWord
inc [PC]
inc [PC]
@@done: test [CC],OverflowMask
jnz @@exit
add [PC],ax
@@exit: ret
endp mcBVC
;*******************************************************************************
proc mcBVS
call GetEffAddr
mov al,[Paged] ; is it a long or short branch?
cmp al,10h ; PAGE2?
je @@16bit
GetByte
inc [PC]
cbw
jmp short @@done
@@16bit: GetWord
inc [PC]
inc [PC]
@@done: test [CC],OverflowMask
jz @@exit
add [PC],ax
@@exit: ret
endp mcBVS
;*******************************************************************************
proc mcBPL
call GetEffAddr
mov al,[Paged] ; is it a long or short branch?
cmp al,10h ; PAGE2?
je @@16bit
GetByte
inc [PC]
cbw
jmp short @@done
@@16bit: GetWord
inc [PC]
inc [PC]
@@done: test [CC],NegativeMask
jnz @@exit
add [PC],ax
@@exit: ret
endp mcBPL
;*******************************************************************************
proc mcBMI
call GetEffAddr
mov al,[Paged] ; is it a long or short branch?
cmp al,10h ; PAGE2?
je @@16bit
GetByte
inc [PC]
cbw
jmp short @@done
@@16bit: GetWord
inc [PC]
inc [PC]
@@done: test [CC],NegativeMask
jz @@exit
add [PC],ax
@@exit: ret
endp mcBMI
;*******************************************************************************
proc mcBGE
call GetEffAddr
mov al,[Paged] ; is it a long or short branch?
cmp al,10h ; PAGE2?
je @@16bit
GetByte
inc [PC]
cbw
jmp short @@done
@@16bit: GetWord
inc [PC]
inc [PC]
@@done: mov bl,[CC]
and bl,NegativeMask+OverflowMask
jz @@ok
cmp bl,NegativeMask+OverflowMask
je @@ok
jmp short @@exit
@@ok: add [PC],ax
@@exit: ret
endp mcBGE
;*******************************************************************************
proc mcBLT
call GetEffAddr
mov al,[Paged] ; is it a long or short branch?
cmp al,10h ; PAGE2?
je @@16bit
GetByte
inc [PC]
cbw
jmp short @@done
@@16bit: GetWord
inc [PC]
inc [PC]
@@done: mov bl,[CC]
and bl,NegativeMask+OverflowMask
jz @@exit
cmp bl,NegativeMask+OverflowMask
je @@exit
add [PC],ax
@@exit: ret
endp mcBLT
;*******************************************************************************
proc mcBGT
call GetEffAddr
mov al,[Paged] ; is it a long or short branch?
cmp al,10h ; PAGE2?
je @@16bit
GetByte
inc [PC]
cbw
jmp short @@done
@@16bit: GetWord
inc [PC]
inc [PC]
@@done: mov bl,[CC]
test bl,ZeroMask
jnz @@exit
and bl,NegativeMask+OverflowMask
jz @@ok
cmp bl,NegativeMask+OverflowMask
je @@ok
jmp short @@exit
@@ok: add [PC],ax
@@exit: ret
endp mcBGT
;*******************************************************************************
proc mcBLE
call GetEffAddr
mov al,[Paged] ; is it a long or short branch?
cmp al,10h ; PAGE2?
je @@16bit
GetByte
inc [PC]
cbw
jmp short @@done
@@16bit: GetWord
inc [PC]
inc [PC]
@@done: mov bl,[CC]
test bl,ZeroMask
jnz @@ok
and bl,NegativeMask+OverflowMask
jz @@exit
cmp bl,NegativeMask+OverflowMask
je @@exit
@@ok: add [PC],ax
@@exit: ret
endp mcBLE
;*******************************************************************************
proc mcLEAX
call GetEffAddr
mov [X],si
and [CC],11111011b
cmp si,0
jnz @@exit
or [CC],00000100b
@@exit: ret
endp mcLEAX
;*******************************************************************************
proc mcLEAY
call GetEffAddr
mov [Y],si
and [CC],11111011b
cmp si,0
jnz @@exit
or [CC],00000100b
@@exit: ret
endp mcLEAY
;*******************************************************************************
proc mcLEAS
call GetEffAddr
mov [S],si
ret
endp mcLEAS
;*******************************************************************************
proc mcLEAU
call GetEffAddr
mov [U],si
ret
endp mcLEAU
;*******************************************************************************
proc mcPSHS
mov si,[PC]
GetByte
inc [PC]
test al,10000000b ; PC?
jz @@1
dec [S]
dec [S]
mov bx,[PC]
xchg bh,bl
mov si,[S]
mov [es:si],bx
@@1: test al,01000000b ; U?
jz @@2
dec [S]
dec [S]
mov bx,[U]
xchg bh,bl
mov si,[S]
mov [es:si],bx
@@2: test al,00100000b ; Y?
jz @@3
dec [S]
dec [S]
mov bx,[Y]
xchg bh,bl
mov si,[S]
mov [es:si],bx
@@3: test al,00010000b ; X?
jz @@4
dec [S]
dec [S]
mov bx,[X]
xchg bh,bl
mov si,[S]
mov [es:si],bx
@@4: test al,00001000b ; DP?
jz @@5
dec [S]
mov bl,[DPR]
mov si,[S]
mov [es:si],bl
@@5: test al,00000100b ; B?
jz @@6
dec [S]
mov bl,[B]
mov si,[S]
mov [es:si],bl
@@6: test al,00000010b ; A?
jz @@7
dec [S]
mov bl,[A]
mov si,[S]
mov [es:si],bl
@@7: test al,00000001b ; CC?
jz @@exit
dec [S]
mov bl,[CC]