32 lines
776 B
ArmAsm
32 lines
776 B
ArmAsm
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; 2019-09-20, Greg King
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;
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; unsigned char get_tv (void);
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; /* Return the video mode the machine is using. */
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;
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.export _get_tv
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.include "cx16.inc"
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.proc _get_tv
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php
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sei ; Don't let interrupts interfere
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; Point to the video output register.
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stz VERA::CTRL ; Use port 0
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lda #<VERA::COMPOSER::VIDEO
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ldx #>VERA::COMPOSER::VIDEO
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ldy #^VERA::COMPOSER::VIDEO
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sta VERA::ADDR
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stx VERA::ADDR+1
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sty VERA::ADDR+2
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lda VERA::DATA0
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plp ; Re-enable interrupts
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and #$07 ; Get the type of output signal
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rts
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.endproc
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