mirror of https://github.com/cc65/cc65.git
204 lines
4.7 KiB
ArmAsm
204 lines
4.7 KiB
ArmAsm
;
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; Ullrich von Bassewitz, 08.08.1998
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;
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; Support routines for the debugger
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;
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.export _DbgInit
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.export _DbgSP, _DbgCS, _DbgHI
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.import popptr1, return0, _DbgEntry, _set_brk, _end_brk
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.import _DbgBreaks
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.import _brk_pc
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.import __ZP_START__ ; Linker generated
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.include "zeropage.inc"
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; C callable function, will install the debugger
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_DbgInit:
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lda #<DbgBreak
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ldx #>DbgBreak
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jmp _set_brk
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; Entry for the break vector.
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DbgBreak:
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pla
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sta retsav
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pla
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sta retsav+1
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cli
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tsx ; Stack pointer
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stx _DbgSP
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jsr DbgSwapZP ; Swap stuff
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lda #<DbgStack ; Set new stack
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sta sp
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lda #>DbgStack
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sta sp+1
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jsr ResetDbgBreaks ; Reset temporary breakpoints
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jsr _DbgEntry ; Call C code
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jsr SetDbgBreaks ; Set temporary breakpoints
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jsr DbgSwapZP ; Swap stuff back
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lda retsav+1
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pha
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lda retsav
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pha
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rts
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; Stack used when in debugger mode
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.bss
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.res 256
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DbgStack:
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; Swap space for the C temporaries
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CTemp:
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_DbgCS: .res 2 ; sp
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_DbgHI: .res 2 ; sreg
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.res (zpsavespace-4) ; Other stuff
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_DbgSP: .res 1
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retsav: .res 2 ; Save buffer for return address
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.code
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; Swap the C temporaries
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DbgSwapZP:
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ldy #zpsavespace-1
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Swap1: ldx CTemp,y
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lda <__ZP_START__,y
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sta CTemp,y
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txa
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sta sp,y
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dey
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bpl Swap1
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rts
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; ----------------------------------------------------------------------------
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; Utility functions
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; Set/reset the breakpoints. We must do that here since the breakpoints
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; may be in the runtime stuff, causing the C part to fail before it has
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; reset the breakpoints. See declaration of struct breakpoint in the C
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; source
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MaxBreaks = 48 ; 4*12
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ResetDbgBreaks:
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ldy #0
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ldx #0
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L4: lda _DbgBreaks+3,x ; Get bk_use
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beq L6 ; Jump if not set
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bpl L5 ; Jump if user breakpoint
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lda #0
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sta _DbgBreaks+3,x ; Clear if temp breakpoint
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L5: lda _DbgBreaks+1,x ; PC hi
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sta ptr1+1
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lda _DbgBreaks,x ; PC lo
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sta ptr1
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lda _DbgBreaks+2,x ; Old OPC
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sta (ptr1),y ; Reset the breakpoint
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L6: inx
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inx
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inx
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inx
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cpx #MaxBreaks ; Done?
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bne L4
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rts
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SetDbgBreaks:
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ldx #0
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ldy #0
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L7: lda _DbgBreaks+3,x ; Get bk_use
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beq L8 ; Jump if not set
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lda _DbgBreaks+1,x ; PC hi
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sta ptr1+1
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lda _DbgBreaks,x ; PC lo
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sta ptr1
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lda (ptr1),y ; Get the breakpoint OPC...
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sta _DbgBreaks+2,x ; ...and save it
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lda #$00 ; Load BRK opcode
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sta (ptr1),y
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L8: inx
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inx
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inx
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inx
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cpx #MaxBreaks ; Done?
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bne L7
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rts
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; Get a free breakpoint slot or return 0
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.export _DbgGetBreakSlot
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_DbgGetBreakSlot:
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ldx #0
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L10: lda _DbgBreaks+3,x ; Get bk_use
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beq L11 ; Jump if not set
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inx
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inx
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inx
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inx
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cpx #MaxBreaks ; Done?
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bne L10
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jmp return0 ; No free slot
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L11: stx tmp1
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lda #<_DbgBreaks
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ldx #>_DbgBreaks
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clc
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adc tmp1
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bcc L12
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inx
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L12: ldy #1 ; Force != 0
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rts
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; Check if a given address has a user breakpoint set, if found, return the
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; slot, otherwise return 0.
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.export _DbgIsBreak
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_DbgIsBreak:
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jsr popptr1 ; Get address
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ldx #0
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L20: lda _DbgBreaks+3,x ; Get bk_use
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beq L21 ; Jump if not set
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bmi L21 ; Jump if temp breakpoint
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lda _DbgBreaks,x ; Low byte of address
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cmp ptr1
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bne L21
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lda _DbgBreaks+1,x ; High byte of address
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cmp ptr1+1
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beq L22
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L21: inx
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inx
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inx
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inx
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cpx #MaxBreaks ; Done?
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bne L20
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jmp return0 ; Not found
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L22: stx tmp1
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lda #<_DbgBreaks
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ldx #>_DbgBreaks
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clc
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adc tmp1
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bcc L23
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inx
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L23: ldy #1 ; Force != 0
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rts
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