Mouse interrupt handler + debug

src/common/debug_txt.asm

@@ -0,0 +1,127 @@
+; =============================================================================
+;  Project  : Custom BIOS / ROM
+;  File     : debug.asm
+;  Author   : frater
+;  Created  : 06 jan 2026
+;
+;  License  : GNU General Public License v3.0 or later (GPL-3.0+)
+;
+;  This program 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.
+;
+;  This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
+;
+; =============================================================================
+
+debug_puts:
+.next:
+	push 	dx
+	mov		dx, DEBUG_PORT
+	lodsb                    	; AL = *SI++
+	test 	al, al
+	jz   	.done
+	out		dx, al
+	jmp  	.next
+.done:
+	pop 	dx
+	ret
+
+debug_putc:
+	push	dx
+	mov		dx, DEBUG_PORT
+	out		dx, al
+	pop 	dx
+	ret
+
+; AL = 0..15 -> print hex digit
+debug_puthex4:
+	and 	al, 0Fh
+	cmp 	al, 9
+	jbe 	.num
+	add 	al, 'A' - 10
+	jmp 	.pout
+.num:
+    add 	al, '0'
+.pout:
+    call debug_putc
+    ret
+
+; AL = byte -> print 2 hex digits
+debug_puthex8:
+	push 	ax
+	mov 	ah, al
+	shr 	al, 4
+	call 	debug_puthex4
+	mov 	al, ah
+	call 	debug_puthex4
+	pop 	ax
+	ret
+
+; AX = word -> print 4 hex digits
+debug_puthex16:
+	push 	ax
+	mov 	al, ah
+	call 	debug_puthex8
+	pop 	ax
+	call 	debug_puthex8
+	ret
+
+
+; --- screen text functions ---
+; AH = page
+; DH = row
+; DL = column
+scr_gotoxy:
+	mov 	ah, 02h
+	mov 	bh, 0	; page 0
+	int 	10h
+	ret
+
+scr_putc:
+	mov 	ah, 0x0E
+	int 	10h
+	ret
+
+; AL = 0..15 -> print hex digit
+scr_puthex4:
+	and 	al, 0Fh	; mask 4 bits low
+	cmp 	al, 9		; is it 0..9 ?
+	jbe 	.num		; yes
+	add 	al, 'A' - 10	; convert to 'A'..'F'
+	jmp 	.pout
+.num:
+    		add 	al, '0'	; convert to '0'..'9'
+.pout:
+    		mov 	ah, 0x0E
+	int 	10h
+    		ret
+
+; AL = byte -> print 2 hex digits
+scr_puthex8:
+	push 	ax
+	push 	bx
+	mov 	bl, al			; save al
+	shr 	al, 4			; 4 bits plus significatifs
+	call 	scr_puthex4
+	mov 	al, bl	; restore al
+	call 	scr_puthex4
+	pop 	bx
+	pop 	ax
+	ret
+
+; AX = word -> print 4 hex digits
+scr_puthex16:
+	push 	ax
+	mov 	al, ah
+	call 	scr_puthex8
+	pop 	ax
+	call 	scr_puthex8
+	ret