58 lines
1.9 KiB
NASM
58 lines
1.9 KiB
NASM
; Arduino terminal driver
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; @author Daniele Verducci
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; config (IO port 0)
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DATA_REG: EQU IO_0
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; variables
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LCD_VAR_SPACE: EQU DRV_VAR_SPACE + 128
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incoming_string: EQU LCD_VAR_SPACE
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; functions
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; Sends string
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; @param BC Pointer to a null-terminated string first character
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Term_print:
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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 (DATA_REG),a ; output char
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inc bc ; increment bc to move to next char
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jp Term_print
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; Writes a single character
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; @param A Value of character to print
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Term_printc:
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out (DATA_REG),a
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ret
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; Reads a single character
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; @return A The read character
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Term_readc:
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in a, (IO_0) ; reads a character
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cp 0
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jp z, Term_readline ; if NULL, ignores it and waits for another character
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ret ; if not NULL, returns it in the a register
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; Reads a line
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; @return BC The pointer to a null-terminated read string
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Term_readline:
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ld ix, incoming_string ; this array will contain read string
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in a, (IO_0) ; reads a character
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; if char is 0 (ascii NULL), ignore it
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cp 0
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jp z, Term_readline ; if 0 (= ascii NULL), ignores it and waits for another character
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; if char is a newline (CR or LF), line is finished.
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cp 10 ; CR
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jp z, term_readline_foundcr ; Found newline. Jump to term_readline_foundcr
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cp 13 ; LF
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jp z, term_readline_foundcr ; Found newline. Jump to term_readline_foundcr
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; At this point the read character is a valid ascii character
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ld (ix), a ; adds char to the read string
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inc ix ; point to next array position
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jp Term_readline
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term_readline_foundcr: ; called when carriage return was found (end of line)
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ld (ix), 0 ; Null-terminate string
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ld bc, incoming_string ; Returns read string
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ret
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