27 lines
397 B
ArmAsm
27 lines
397 B
ArmAsm
.define Printhex
|
|
|
|
! This subroutine print the contents of register A to the screen
|
|
! in hexadecimal form.
|
|
! The subroutine WRCH is a special one provided by the BBC
|
|
! microcomputer.
|
|
|
|
|
|
Printhex:
|
|
pha ! save A
|
|
lsr a
|
|
lsr a
|
|
lsr a
|
|
lsr a ! get four high bits
|
|
jsr 1f
|
|
pla ! restore A
|
|
and #0Fh ! get four low bits
|
|
jsr 1f
|
|
rts
|
|
1: sed ! print in hex
|
|
clc
|
|
adc #90h
|
|
adc #40h
|
|
cld
|
|
jmp WRCH
|
|
|
|
|