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collapseos/blk/289
Virgil Dupras e4a4a9800d z80: Use BC as IP register instead of IY
It's a bit more inconvenient in terms of register protection (BC
is much more generally useful than IY), but it makes tight spots
such as next and execute much faster, so I think it's worth it.
2020-07-06 23:31:00 -04:00

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( compiled word ) L1 FSET ( execute B301 )
( 1. Push current IP to RS
2. Set new IP to the second atom of the list
3. Execute the first atom of the list. )
IX INCd, IX INCd,
0 IX+ C LDIXYr,
1 IX+ B LDIXYr,
EXDEHL, ( HL points to PFA )
( While we inc, dereference into DE for execute call later. )
LDDE(HL),
HL INCd,
B H LDrr, C L LDrr, ( --> IP )
JR, lblexec BWR ( execute-B287 )