; (TEDMon).
;
- .import popax
- .import __hextab, OffsetTab, AdrFlagTab
- .import SymbolTab1, SymbolTab2, MnemoTab1, MnemoTab2
+ .import popax
+ .import __hextab, OffsetTab, AdrFlagTab
+ .import SymbolTab1, SymbolTab2, MnemoTab1, MnemoTab2
; -------------------------------------------------------------------------
; Equates for better readability
- .importzp sreg, tmp1, tmp2, tmp3, tmp4, ptr1, ptr2, ptr3
+ .importzp sreg, tmp1, tmp2, tmp3, tmp4, ptr1, ptr2, ptr3
-BufIndex = tmp1 ; Index into output buffer
-OperandLen = tmp2 ; Length of operand
-BufLen = tmp3 ; Length of output buffer
-AdrFlagBuf = tmp4 ; Flag for addressing mode
-YSave = sreg ; Temp storage
-XSave = sreg+1 ; Dito
-BufPtr = ptr1 ; Pointer to output buffer
-MemPtr = ptr2 ; Pointer to memory to disassemble
-MnemoBuf = ptr3 ; Buffer for decoding mnemonic
+BufIndex = tmp1 ; Index into output buffer
+OperandLen = tmp2 ; Length of operand
+BufLen = tmp3 ; Length of output buffer
+AdrFlagBuf = tmp4 ; Flag for addressing mode
+YSave = sreg ; Temp storage
+XSave = sreg+1 ; Dito
+BufPtr = ptr1 ; Pointer to output buffer
+MemPtr = ptr2 ; Pointer to memory to disassemble
+MnemoBuf = ptr3 ; Buffer for decoding mnemonic
; -------------------------------------------------------------------------
; Main entries
- .export _DbgDisAsm, _DbgDisAsmLen
-
-.proc _DbgDisAsm
- sta BufLen ; Save the buffer length
- jsr popax ; Get the buffer pointer
- sta BufPtr
- stx BufPtr+1
- jsr popax ; Get the address
- sta MemPtr
- stx MemPtr+1
- lda #0
- sta BufIndex ; Initialize index into buffer
- jsr DisAssLine ; Disassemble one line into the buffer
-
- lda BufLen ; Get requested length
- sec
- sbc BufIndex
- beq L2
- tax ; Count into X
- ldy BufIndex
- lda #$20 ; Get a space
-L1: sta (BufPtr),y
- iny
- dex
- bne L1
-L2: lda #0 ; Add C string terminator
- sta (BufPtr),y
- beq disassret
+ .export _DbgDisAsm, _DbgDisAsmLen
+
+.proc _DbgDisAsm
+ sta BufLen ; Save the buffer length
+ jsr popax ; Get the buffer pointer
+ sta BufPtr
+ stx BufPtr+1
+ jsr popax ; Get the address
+ sta MemPtr
+ stx MemPtr+1
+ lda #0
+ sta BufIndex ; Initialize index into buffer
+ jsr DisAssLine ; Disassemble one line into the buffer
+
+ lda BufLen ; Get requested length
+ sec
+ sbc BufIndex
+ beq L2
+ tax ; Count into X
+ ldy BufIndex
+ lda #$20 ; Get a space
+L1: sta (BufPtr),y
+ iny
+ dex
+ bne L1
+L2: lda #0 ; Add C string terminator
+ sta (BufPtr),y
+ beq disassret
.endproc
_DbgDisAsmLen:
- sta MemPtr ; Save address
- stx MemPtr+1
- ldy #$00
- lda (MemPtr),y ; Get the opcode from memory...
- jsr AnalyzeOPCode ; ...and analyze it
+ sta MemPtr ; Save address
+ stx MemPtr+1
+ ldy #$00
+ lda (MemPtr),y ; Get the opcode from memory...
+ jsr AnalyzeOPCode ; ...and analyze it
disassret:
- ldx OperandLen ; Get length of operand
- inx ; Adjust for opcode byte
- txa
+ ldx OperandLen ; Get length of operand
+ inx ; Adjust for opcode byte
+ txa
ldx #$00 ; Clear high byte
rts
Put3Spaces:
- jsr PutSpace
+ jsr PutSpace
Put2Spaces:
- jsr PutSpace
+ jsr PutSpace
PutSpace:
- lda #$20
+ lda #$20
PutChar:
- sty YSave ; Save Y
- ldy BufIndex ; Get current line pointer
- cpy BufLen ; Be sure not to overflow the buffer
- bcs PC9
- sta (BufPtr),y ; store character
- iny ; bump index
- sty BufIndex
-PC9: ldy YSave ; get old value
- rts
+ sty YSave ; Save Y
+ ldy BufIndex ; Get current line pointer
+ cpy BufLen ; Be sure not to overflow the buffer
+ bcs PC9
+ sta (BufPtr),y ; store character
+ iny ; bump index
+ sty BufIndex
+PC9: ldy YSave ; get old value
+ rts
; Print the 16 bit hex value in X/Y
PutHex16:
- txa
- jsr PutHex8
- tya
+ txa
+ jsr PutHex8
+ tya
; Print 8 bit value in A, save X and Y
PutHex8:
- stx XSave
- sty YSave
- ldy BufIndex
- pha
- lsr a
- lsr a
- lsr a
- lsr a
- tax
- lda __hextab,x
- sta (BufPtr),y
- iny
- pla
- and #$0F
- tax
- lda __hextab,x
- sta (BufPtr),y
- iny
- sty BufIndex
- ldy YSave
- ldx XSave
- rts
+ stx XSave
+ sty YSave
+ ldy BufIndex
+ pha
+ lsr a
+ lsr a
+ lsr a
+ lsr a
+ tax
+ lda __hextab,x
+ sta (BufPtr),y
+ iny
+ pla
+ and #$0F
+ tax
+ lda __hextab,x
+ sta (BufPtr),y
+ iny
+ sty BufIndex
+ ldy YSave
+ ldx XSave
+ rts
; -------------------------------------------------------------------------
; Disassemble one line
DisAssLine:
- ldy MemPtr
- ldx MemPtr+1
- jsr PutHex16 ; Print the address
- jsr Put2Spaces ; Add some space
- ldy #$00
- lda (MemPtr),y ; Get the opcode from memory...
- jsr AnalyzeOPCode ; ...and analyze it
- pha ; Save mnemonic
- ldx OperandLen ; Number of bytes
+ ldy MemPtr
+ ldx MemPtr+1
+ jsr PutHex16 ; Print the address
+ jsr Put2Spaces ; Add some space
+ ldy #$00
+ lda (MemPtr),y ; Get the opcode from memory...
+ jsr AnalyzeOPCode ; ...and analyze it
+ pha ; Save mnemonic
+ ldx OperandLen ; Number of bytes
; Print the bytes that make up the instruction
- inx
-L2083: dex
- bpl L208C ; Print the instruction bytes
- jsr Put3Spaces ; If none left, print spaces instead
- jmp L2094
-L208C: lda (MemPtr),y ; Get a byte from memory
- jsr PutHex8 ; ...and print it
- jsr PutSpace ; Add some space
+ inx
+L2083: dex
+ bpl L208C ; Print the instruction bytes
+ jsr Put3Spaces ; If none left, print spaces instead
+ jmp L2094
+L208C: lda (MemPtr),y ; Get a byte from memory
+ jsr PutHex8 ; ...and print it
+ jsr PutSpace ; Add some space
-L2094: iny ; Next one...
- cpy #$03 ; Maximum is three
- bcc L2083 ;
+L2094: iny ; Next one...
+ cpy #$03 ; Maximum is three
+ bcc L2083 ;
- jsr Put2Spaces ; Add some space after bytes
+ jsr Put2Spaces ; Add some space after bytes
; Print the assembler mnemonic
- pla ; Get mnemonic code
- ldx #$03
- jsr PutMnemo ; Print the mnemonic
- ldx #$06
+ pla ; Get mnemonic code
+ ldx #$03
+ jsr PutMnemo ; Print the mnemonic
+ ldx #$06
; Print the operand
-L20A4: cpx #$03
- bne L20BA
- ldy OperandLen
- beq L20BA
-
-L20AC: lda AdrFlagBuf
- cmp #$E8 ; Branch?
- lda (MemPtr),y ; Get branch offset
- bcs GetBranchAdr ; If branch: Calculate address
- jsr PutHex8 ; Otherwise print 8bit value
- dey
- bne L20AC
-
-L20BA: asl AdrFlagBuf
- bcc L20CC
- lda SymbolTab1-1,x
- jsr PutChar
- lda SymbolTab2-1,x
- beq L20CC
- jsr PutChar
-
-L20CC: dex
- bne L20A4
- rts
+L20A4: cpx #$03
+ bne L20BA
+ ldy OperandLen
+ beq L20BA
+
+L20AC: lda AdrFlagBuf
+ cmp #$E8 ; Branch?
+ lda (MemPtr),y ; Get branch offset
+ bcs GetBranchAdr ; If branch: Calculate address
+ jsr PutHex8 ; Otherwise print 8bit value
+ dey
+ bne L20AC
+
+L20BA: asl AdrFlagBuf
+ bcc L20CC
+ lda SymbolTab1-1,x
+ jsr PutChar
+ lda SymbolTab2-1,x
+ beq L20CC
+ jsr PutChar
+
+L20CC: dex
+ bne L20A4
+ rts
; If the instruction is a branch, calculate the absolute address of the
; branch target and print it.
GetBranchAdr:
- jsr L20DD
- clc
- adc #$01
- bne L20D9
- inx ; Bump high byte
-L20D9: tay
- jmp PutHex16 ; Output address
-
-L20DD: ldx MemPtr+1
- tay
- bpl L20E3
- dex
-L20E3: adc MemPtr
- bcc L20E8
- inx ; Bump high byte
-L20E8: rts
+ jsr L20DD
+ clc
+ adc #$01
+ bne L20D9
+ inx ; Bump high byte
+L20D9: tay
+ jmp PutHex16 ; Output address
+
+L20DD: ldx MemPtr+1
+ tay
+ bpl L20E3
+ dex
+L20E3: adc MemPtr
+ bcc L20E8
+ inx ; Bump high byte
+L20E8: rts
; -------------------------------------------------------------------------
; Subroutine to analyze an opcode byte in A. Will return a byte that
; instruction in OperandLen
AnalyzeOPCode:
- tay
- lsr a
- bcc L20F8
- lsr a
- bcs L2107
- cmp #$22
- beq L2107
- and #$07
- ora #$80
-L20F8: lsr a
- tax
- lda OffsetTab,x
- bcs L2103
- lsr a
- lsr a
- lsr a
- lsr a
-L2103: and #$0F
- bne L210B
-L2107: ldy #$80
- lda #$00
-L210B: tax
- lda AdrFlagTab,x
- sta AdrFlagBuf
- and #$03
- sta OperandLen
- tya
- and #$8F
- tax
- tya
- ldy #$03
- cpx #$8A
- beq L212B
-
-L2120: lsr a
- bcc L212B
- lsr a
-L2124: lsr a
- ora #$20
- dey
- bne L2124
- iny
-L212B: dey
- bne L2120
- rts
+ tay
+ lsr a
+ bcc L20F8
+ lsr a
+ bcs L2107
+ cmp #$22
+ beq L2107
+ and #$07
+ ora #$80
+L20F8: lsr a
+ tax
+ lda OffsetTab,x
+ bcs L2103
+ lsr a
+ lsr a
+ lsr a
+ lsr a
+L2103: and #$0F
+ bne L210B
+L2107: ldy #$80
+ lda #$00
+L210B: tax
+ lda AdrFlagTab,x
+ sta AdrFlagBuf
+ and #$03
+ sta OperandLen
+ tya
+ and #$8F
+ tax
+ tya
+ ldy #$03
+ cpx #$8A
+ beq L212B
+
+L2120: lsr a
+ bcc L212B
+ lsr a
+L2124: lsr a
+ ora #$20
+ dey
+ bne L2124
+ iny
+L212B: dey
+ bne L2120
+ rts
; -------------------------------------------------------------------------
; Print the mnemonic with code in A (that code was returned by
; AnalyzeOpcode).
PutMnemo:
- tay
- lda MnemoTab1,y
- sta MnemoBuf
- lda MnemoTab2,y
- sta MnemoBuf+1
-L213A: lda #$00
- ldy #$05 ; 3*5 bits in two bytes
-L213E: asl MnemoBuf+1
- rol MnemoBuf
- rol a
- dey
- bne L213E
- adc #$3F
- jsr PutChar
- dex
- bne L213A
- jmp PutSpace
+ tay
+ lda MnemoTab1,y
+ sta MnemoBuf
+ lda MnemoTab2,y
+ sta MnemoBuf+1
+L213A: lda #$00
+ ldy #$05 ; 3*5 bits in two bytes
+L213E: asl MnemoBuf+1
+ rol MnemoBuf
+ rol a
+ dey
+ bne L213E
+ adc #$3F
+ jsr PutChar
+ dex
+ bne L213A
+ jmp PutSpace
projects / cc65 / blobdiff