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cx16.numbanks() now returns a word because the result can be >255

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Irmen de Jong 2023-02-08 00:51:34 +01:00
parent edf56d34f8
commit 79d0fb0b52
1 changed files with 11 additions and 3 deletions
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14
compiler/res/prog8lib/cx16/syslib.p8
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@ -460,15 +460,23 @@ inline asmsub getrambank() -> ubyte @A {
}}
}
asmsub numbanks() -> ubyte @A {
asmsub numbanks() -> uword @AY {
; -- uses MEMTOP's cx16 extension to query the number of available RAM banks. (each is 8 Kb)
; Note: when 0 is returned, it doesn't mean 'zero banks', instead it means 256 banks (=2Mb banked RAM),
; Note that the number of such banks can be bigger than 255 so a word is returned, but mostly
; the A register could suffice as the lsb.
; The maximum number of banks is 256 = 2 Megabytes of banked Ram aka Hiram. (Y=1 and A=0 in this case).
; MEMTOP itself reports 0 in this case which we change into 256 for convenience.
; It reporting 0 doesn't mean 'zero banks', instead it means 256 banks (=2Mb banked RAM),
; as there is no X16 without at least 1 page of banked RAM.
%asm {{
phx
sec
jsr c64.MEMTOP
plx
ldy #0
cmp #0
bne +
iny
+ plx
rts
}}
}