pato-z80-home-computer/pat80-computer/software/z80-assembly/os/drivers/arduino_terminal.asm

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; Arduino terminal driver
; @author Daniele Verducci
2021-07-11 09:49:42 +02:00
; @language: Z80 ASM
;
;
; This file is part of Pat80 Memory Monitor.
;
; Pat80 Memory Monitor is free software: you can redistribute it and/or modify
; it under the terms of the GNU General Public License as published by
; the Free Software Foundation, either version 3 of the License, or
; (at your option) any later version.
;
; Pat80 Memory Monitor is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
; GNU General Public License for more details.
;
; You should have received a copy of the GNU General Public License
; along with Pat80 Memory Monitor. If not, see <http://www.gnu.org/licenses/>.
; config (IO port 0)
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TERM_DATA_REG: EQU IO_0
TERM_DATA_AVAIL_REG: EQU IO_0 + 1
; variables
TERM_VAR_SPACE: EQU DRV_VAR_SPACE + 128
incoming_string: EQU TERM_VAR_SPACE
; functions
; Sends string
; @param BC Pointer to a null-terminated string first character
Term_print:
ld a, (bc) ; bc is the pointer to passed string's first char
cp 0 ; compare A content with 0 (subtract 0 from value and set zero flag Z if result is 0)
ret z ; if prev compare is true (Z flag set), string is finished, return
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out (TERM_DATA_REG),a ; output char
inc bc ; increment bc to move to next char
jp Term_print
; Writes a single character
; @param A Value of character to print
Term_printc:
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out (TERM_DATA_REG),a
ret
; Reads a single character. 0s are ignored (can be used with keyboard).
; Doesn't check DATA_AVAILABLE register of parallel port, because a 0 byte
; is ignored anyway (it represents the ASCII NUL control char).
; @return A The read character
Term_readc:
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in a, (TERM_DATA_REG) ; reads a character
add a, 0
jp z, Term_readc ; if char is 0 (NULL), ignores it and waits for another character
ret ; if not NULL, returns it in the a register
; Reads a line. 0s are ignored (can be used with keyboard)
; Doesn't check DATA_AVAILABLE register of parallel port, because a 0 byte
; is ignored anyway (it represents the ASCII NUL control char).
; @return BC The pointer to a null-terminated read string
Term_readline:
ld bc, incoming_string ; this array will contain read string
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in a, (TERM_DATA_REG) ; reads a character
; if char is 0 (ascii NULL), ignore it
add a, 0
jp z, Term_readline ; if 0 (= ascii NULL), ignores it and waits for another character
; if char is a newline (CR or LF), line is finished.
cp 10 ; CR
jp z, term_readline_foundcr ; Found newline. Jump to term_readline_foundcr
cp 13 ; LF
jp z, term_readline_foundcr ; Found newline. Jump to term_readline_foundcr
; At this point the read character is a valid ascii character
ld (bc), a ; adds char to the read string
inc bc ; point to next array position
jp Term_readline
term_readline_foundcr: ; called when carriage return was found (end of line)
;ld (bc), 0 ; Null-terminate string
ld bc, incoming_string ; Returns read string pointer
ret
; Reads the first available byte on the serial port using the DATA register.
; Waits for the Terminal DATA_AVAILABLE register to be non-zero before reading.
; 0s are not ignored (cannot be used with keyboard)
; Affects NO condition bits!
; @return the available byte, even if 0
Term_readb:
in a, (TERM_DATA_AVAIL_REG)
cp 0
jp z, Term_readb
in a, (TERM_DATA_REG) ; reads a byte
ret