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37 lines
779 B
ArmAsm
Executable File
37 lines
779 B
ArmAsm
Executable File
;
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; Marco van den Heuvel, 2018-04-20
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;
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; unsigned char detect_c128 (void);
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;
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;/* Check for the presence of a C128 in C64 mode.
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; *
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; * Possible return values:
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; * 0x00 : C128 in C64 mode not present
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; * 0x01 : C128 in C64 mode present
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; */
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.export _detect_c128
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.include "accelerator.inc"
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_detect_c128:
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lda #$00
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tax
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; Make sure the CPU is a 8502
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.byte $1A ; NOP on 8502, INA on 65(S)C(E)02, 4510 and 65816
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beq found
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.byte $3A ; decrement A again, so a #$00 can be returned
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rts
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found:
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; Make sure a C128 VICIIe is present
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ldy C128_VICIIE_CLK
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cpy #$FF
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beq not_found
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lda #$01
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not_found:
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rts
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