69 lines
1.4 KiB
ArmAsm
69 lines
1.4 KiB
ArmAsm
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; Based on BSM (Bit Shifter's Monitor)
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Mon_Memory:
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jsr Set_MODE_80
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lda #$00
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sta Addr_Mode ; by default use C64-style addressing
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jsr Get_Addr_To_LAC ; get 1st parameter (start address)
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+beq Mon_Error
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jsr LAC_To_LPC ; Long_PC = start address
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jsr Get_Addr_To_LAC ; get 2nd parameter (end address)
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bne @calcdiff
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lda #$10 ; by default display 16 rows
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sta Long_CT+0
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lda #$00
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sta Long_CT+1
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sta Long_CT+2
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sta Long_CT+3
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bra @loop
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@calcdiff:
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jsr LAC_Minus_LPC ; Long_CT = range
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+bcc Mon_Error ; error if negative range
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ldx #$04 ; for 80 character mode - 16 (2^4) bytes/line
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bbr7 MODE_80,@shift
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dex ; for 40 character mode - 8 (2^3) bytes/line
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@shift:
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clc
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ror Long_CT+3
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ror Long_CT+2
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ror Long_CT+1
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ror Long_CT+0
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dex
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bne @shift ; at the ned of loop Long_CT contains number of rows to show minus 1
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@loop:
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jsr Dump_Row
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jsr STOP
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beq @exit ; end if STOP pressed
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sec ; XXX consider moving this to separate subroutine
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lda Long_CT+0
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sbc #$01
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sta Long_CT+0
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lda Long_CT+1
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sbc #$00
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sta Long_CT+1
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lda Long_CT+2
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sbc #$00
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sta Long_CT+2
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lda Long_CT+3
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sbc #$00
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sta Long_CT+3
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bcs @loop
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@exit:
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jmp Main
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