Implemented read char and readline in arduino terminal driver

assembly/bios/driver_arduino_terminal.asm

@@ -4,6 +4,10 @@
 ; config (IO port 0)
 DATA_REG: EQU IO_0
 
+; variables
+LCD_VAR_SPACE: EQU DRV_VAR_SPACE + 128
+incoming_string: EQU LCD_VAR_SPACE
+
 ; functions
 
 ; Sends string
@@ -21,3 +25,33 @@ Term_print:
 Term_printc:
     out (DATA_REG),a
     ret
+
+; Reads a single character
+; @return A The read character
+Term_readc:
+    in a, (IO_0)    ; reads a character
+    cp 0
+    jp z, Term_readline     ; if NULL, ignores it and waits for another character
+    ret ; if not NULL, returns it in the a register
+
+; Reads a line
+; @return BC The pointer to a null-terminated read string
+Term_readline:
+    ld ix, incoming_string  ; this array will contain read string
+    in a, (IO_0)    ; reads a character
+    ; if char is 0 (ascii NULL), ignore it
+    cp 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 (ix), a ; adds char to the read string
+    inc ix  ; point to next array position
+    jp Term_readline
+    term_readline_foundcr:   ; called when carriage return was found (end of line)
+    ld (ix), 0 ; Null-terminate string
+    ld bc, incoming_string  ; Returns read string
+    ret