33 lines
458 B
ArmAsm
33 lines
458 B
ArmAsm
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.define Printhex
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.sect .text
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.sect .rom
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.sect .data
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.sect .bss
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.sect .text
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! This subroutine print the contents of register A to the screen
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! in hexadecimal form.
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! The subroutine WRCH is a special one provided by the BBC
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! microcomputer.
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Printhex:
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pha ! save A
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lsr a
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lsr a
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lsr a
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lsr a ! get four high bits
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jsr 1f
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pla ! restore A
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and #0x0F ! get four low bits
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jsr 1f
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rts
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1: sed ! print in hex
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clc
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adc #0x90
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adc #0x40
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cld
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jmp WRCH
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