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52 lines
635 B
ArmAsm
52 lines
635 B
ArmAsm
detect_aux_ram:
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; if Apple IIgs or IIc assume 128k
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; FIXME: Apple IIgs there are routines to get more accurate count
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lda APPLEII_MODEL
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cmp #'g'
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beq return_64k
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cmp #'c'
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beq return_64k
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cmp #'e'
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bne return_0k ; assume none if not IIe
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; enable AUX zp
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sta $C009
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; write $AA to $FF FF:AUX = AA, FF:MAIN=??
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lda #$AA
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sta $FF
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; disable AUX zp
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sta $C008
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; write $55 to $FF FF:AUX=AA, FF:MAIN=55
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lda #$55
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sta $FF
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; enable AUX zp
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sta $C009
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ldx $FF
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; disable AUX zp ; if aux, then X=AA, else X=55
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sta $C008
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cpx #$AA
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bne return_0k
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return_64k:
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lda #64
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rts
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return_1k:
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lda #1
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rts
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return_0k:
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lda #0
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rts
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