The BBC and Master Computer Public Domain Library
FALSE (Clear IWA)
Submitted by Steve Fewell
Routine: FALSE
Name: Clear IWA [also: IWA = FALSE]
Starting Address: &ABE8
Entry criteria: None
Exit: IWA contains zero.
Description:
Clears the IWA to zero, and sets A to #&40 to
show that an Integer number is being processed.
Disassembly for the Clear IWA routine
| ABE8 | 162 000 | A2 00 | LDX#&00 | |
| ABEA | 128 241 | 80 F1 | BRA -15 --> &ABDD Store X (zero) in every byte of the IWA |
Store X in every byte of the IWA:
| ABDD | * | 134 042 | 86 2A | STX &2A |
| ABDF | + | 134 043 | 86 2B | STX &2B |
| ABE1 | , | 134 044 | 86 2C | STX &2C |
| ABE3 | - | 134 045 | 86 2D | STX &2D |
| ABE5 | @ | 169 064 | A9 40 | LDA#&40 |
| ABE7 | ` | 096 | 60 | RTS |
