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45 lines
1.3 KiB
ArmAsm
45 lines
1.3 KiB
ArmAsm
;
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; 2016-02-28, Groepaz
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; 2022-03-29, Greg King
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;
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; unsigned char cpeekrevers (void);
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; /* Return the reverse attribute from the current cursor position.
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; ** If the character is reversed, then return 1; return 0 otherwise.
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; */
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;
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.export _cpeekrevers
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.include "cx16.inc"
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.macpack generic
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screen_addr := $1B000 ; VRAM address of text screen
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_cpeekrevers:
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php
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lda CURS_FLAG ; is the cursor currently off?
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bne @L1
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sei ; don't let cursor blinking interfere
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ldx CURS_STATE ; is cursor currently displayed?
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beq @L1 ; jump if not
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lda CURS_CHAR ; get screen code under cursor
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bra @L2
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@L1: stz VERA::CTRL ; use port 0
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lda CURS_Y
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add #<(>screen_addr)
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sta VERA::ADDR+1 ; set row number
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lda #^screen_addr
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sta VERA::ADDR+2
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lda CURS_X ; get character column
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asl a ; each character has two bytes
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sta VERA::ADDR
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lda VERA::DATA0 ; get screen code
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@L2: plp
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and #%10000000 ; get reverse bit
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asl a
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tax ; ldx #>$0000
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rol a ; return boolean value
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rts
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