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Clear FWA

Submitted by Steve Fewell

Routine: aclear
Name: Clear FWA
Starting Address: &A6B4
Entry criteria: None
Exit
: Every byte in the FWA contains the value 0 (this indicates the number 0).

Description:
Sets every byte of the FWA (locations &2E to &35) to zero. This uniquely identifies the number zero.

This routine can be jumped in at address A6B8, in this case all bytes of the FWA are cleared, except for the Exponent and Mantissa byte 1 (the most significant byte of the mantissa).


Disassembly for the Clear FWA routine

A6B4 d0 100 048 64 30 STZ &30
A6B6 d1 100 049 64 31 STZ &31
A6B8 d. 100 046 64 2E STZ &2E
A6BA d/ 100 047 64 2F STZ &2F
A6BC d2 100 050 64 32 STZ &32
A6BE d3 100 051 64 33 STZ &33
A6C0 d4 100 052 64 34 STZ &34
A6C2 d5 100 053 64 35 STZ &35
A6C4 ` 096 60 RTS

 


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