The BBC and Master Computer Public Domain Library
A5E9 Floating-Point Reciple (FWA=1/FWA)
Submitted by Steve Fewell
Routine:areciple
Name: Floating-Point Reciple
Starting Address: &A5E9
Entry criteria: The FWA Contains a Floating-Point value.
Exit: The FWA contains the value of FWA = 1 / FWA.
Description:
Set argp to point to the Floating-Point Constant at &BF92 which contains the value 1.0.
This value is stored in the Floating-Point Constant table.
Jump to the Floating-Point divide routine to set the FWA to: FWA = argp / FWA.
The FWA will now contain the reciple value of the previous value in the FWA.
Disassembly for the Floating-Point Reciple routine
| A5E9 | 169 146 | A9 92 | LDA#&92 | |
| A5EB | 032 139 165 | 20 8B A5 | JSR &A58B | |
| A5EE | ...Floating-Point Divide |
Disassembly for the A58B Set argp to &BF00 + A
| A589 | . | 169 046 | A9 2E | LDA#&2E |
| A58B | J | 133 074 | 85 4A | STA &4A |
| A58D | 169 191 | A9 BF | LDA#&BF | |
| A58F | K | 133 075 | 85 4B | STA &4B |
| A591 | ` | 096 | 60 | RTS |
