Code refactoring, working char read and print, working line print, not working line read

README.md

@@ -37,6 +37,9 @@ Passarne il puntatore ad una funzione:
 ld bc, myVar
 call lcd_print
 ```
+### Segmentation fault
+Controllare che non si stia puntando ad un registro con le parentesi:
+`ld (ix), a`
 
 # C
 ## Deploy

assembly/bios/driver_arduino_terminal.asm

@@ -5,8 +5,8 @@
 DATA_REG: EQU IO_0
 
 ; variables
-LCD_VAR_SPACE: EQU DRV_VAR_SPACE + 128
-incoming_string: EQU LCD_VAR_SPACE
+TERM_VAR_SPACE: EQU DRV_VAR_SPACE + 128
+incoming_string: EQU TERM_VAR_SPACE
 
 ; functions
 
@@ -29,29 +29,29 @@ Term_printc:
 ; 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
+    in a, (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
 ; @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
+    ld bc, incoming_string  ; this array will contain read string
+    in a, (DATA_REG)    ; reads a character
     ; if char is 0 (ascii NULL), ignore it
-    cp 0
+    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. 
+    ; 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
+    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 (ix), 0 ; Null-terminate string
-    ld bc, incoming_string  ; Returns read string
+    ld (bc), 0 ; Null-terminate string
+    ld bc, incoming_string  ; Returns read string pointer
     ret

assembly/bios/driver_hd44780.asm

@@ -1,5 +1,11 @@
 ; HD44780 20x4 characters LCD display driver
 ; @author Daniele Verducci
+;
+; USAGE:
+; STR: DB "Hello world!",0          <-- null terminated string
+; call Lcd_init                     <-- inits hd44780 controller
+; ld bc, STR                        <-- load pointer to string's first char in reg BC
+; call Lcd_print                    <-- this function will print the string
 
 ; LCD config (IO port 0)
 LCD_INSTR_REG: EQU IO_0

assembly/bios/main.asm

@@ -2,7 +2,7 @@ jp Sysinit     ; Startup vector: DO NOT MOVE! Must be the first instruction
 
 ; Pat80 BIOS v0.01
 ; @author: Daniele Verducci
-; 
+;
 ; MEMORY MAP
 ;   ROM is at 0x0000
 ;   RAM is at 0x8000
@@ -78,30 +78,23 @@ Readline:
 
 ; System initialization
 Sysinit:
-    ;call Lcd_init
-
-    ; position to line 2 char 3
-    ;ld b, 1
-    ;ld c, 1
-    ;call Lcd_locate
-
-    ; I/O TEST
-     
-    ; write characters to display
     ld bc, SYSINIT_GREETING
-    call Lcd_print      ; write string to screen
-    _io_test_loop:   
-        in a, (IO_0)    ; legge dal terminale
-        cp 0
-        jp z, _io_test_loop
-        ;sub a, 32   ; trasforma in maiuscola (ascii - 32) 
-        out (IO_0), a   ; scrive la lettera trasformata        
+    call Print
+   
+    _io_test_loop:
+        call Readline
+        call Print
+
+        ; call Printc
+        ; call Readline
+        ; ld a, (bc)
+        ; cp a, 0
+        ; jp z, _io_test_loop
+        ; ld (APP_VAR_SPACE), bc
+        ; ld bc, SAYS
+        ; call Print
+        ; ld bc, (APP_VAR_SPACE)
+        ; call Print
     jp _io_test_loop
 
-    halt
-
-    ; poll keyboard
-    ;_poll_keyb:
-    ;call Keyb_read
-    ;jp _poll_keyb