41 lines
939 B
NASM
41 lines
939 B
NASM
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; SYSTEM CONFIGURATION
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LCD_INSTR_REG: EQU %00000000
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LCD_DATA_REG: EQU %00000001
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; System initialization
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call lcd_init
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; write characters to display
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ld bc, hello_world
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call lcd_write ; write string to screen
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halt
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lcd_init:
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;reset procedure
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ld a,%00111000
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out (LCD_INSTR_REG),a
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ld a,%00001000
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out (LCD_INSTR_REG),a
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ld a,%00000001
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out (LCD_INSTR_REG),a
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;init procedure
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ld a,%00111000
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out (LCD_INSTR_REG),a
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ld a,%00001110
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out (LCD_INSTR_REG),a
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ret
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lcd_write:
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ld a, (bc) ; bc is the pointer to passed string's first char
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cp 0 ; compare A content with 0 (subtract 0 from value and set zero flag Z if result is 0)
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ret z ; if prev compare is true (Z flag set), string is finished, return
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out (LCD_DATA_REG),a ; output char
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inc bc ; increment bc to move to next char
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jp lcd_write
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hello_world:
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DB "Lorem ipsum",0 ; null terminated string
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