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53 lines
896 B
ArmAsm
53 lines
896 B
ArmAsm
;
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; Stefan Haubenthal, Jul 12 2003
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;
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; unsigned char get_ostype(void)
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;
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.constructor initostype
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.export _get_ostype, ostype
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; Identify machine according to:
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; "Apple II Miscellaneous TechNote #7: Apple II Family Identification"
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initostype:
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ldx #$01 ; Start out with a plain Apple ][
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lda $FBB3
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cmp #$38
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beq identified
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inx ; It's at least an Apple ][+
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cmp #$EA
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bne apple2e
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lda $FB1E
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cmp #$AD
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beq identified
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inx ; It's an Apple /// in emulation mode
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bne identified ; Branch always
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apple2e:
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ldx #$04 ; It's at least an Apple //e
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lda $FBC0
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cmp #$EA
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beq identified
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inx ; It's at least an enhanced Apple //e
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cmp #$E0
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bne apple2c
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lda $FBDD
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cmp #$02
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bne identified
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inx ; It's an Apple //e Option Card
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bne identified ; Branch always
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apple2c:
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ldx #$07 ; It's an Apple //c
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identified:
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stx ostype
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rts
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_get_ostype:
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lda ostype
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ldx #$00
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rts
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.bss
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ostype: .res 1
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