ZeusWPI/ass_messages
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add UART init code and send every char to UART

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This commit is contained in:
Tibo 2021-10-05 16:02:17 +02:00
parent ab6cede5b7
commit aabea9d9f5
1 changed files with 25 additions and 3 deletions
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28
messages.asm
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@ -11,6 +11,15 @@ PIT_CH2_DATA_PORT equ 0x42 ; PIT channel 2 data port
;; see http://www.ctyme.com/intr/int-10.htm for interrupts ;; see http://www.ctyme.com/intr/int-10.htm for interrupts
start: start:
mov sp, 0x2000 ; initialise stack pointer
;; initialise serial port
mov ah, 0x0 ; initialise UART
mov al, 0b111_00_0_11 ; baud 9600, no parity, 1 stop bit, 8 data bits
mov dx, 0x0 ; COM1
int 0x14
;; Use color mode ;; Use color mode
mov ax, VIDEO_MODE mov ax, VIDEO_MODE
int 10h int 10h
@ -31,12 +40,13 @@ mov dh, HEIGHT ; row (bottommost row)
mov dl, 0x00 ; col (leftmost col) mov dl, 0x00 ; col (leftmost col)
int 0x10 int 0x10
mov sp, 0x2000 ; initialise stack pointer
.loop: .loop:
mov ah, 0x00 ; Read a character ;; read a character, ASCII in al
mov ah, 0x00 ; Read character
int 0x16 int 0x16
call UART_send_char
cmp al, 0x08 ; backspace cmp al, 0x08 ; backspace
je change_color_mode je change_color_mode
@ -52,6 +62,18 @@ mov sp, 0x2000 ; initialise stack pointer
call newline call newline
jmp .loop jmp .loop
;; Prints a character in al to the serial port
;;
;; CLOBBERS
;; - ax
;; - dx
UART_send_char:
mov ah, 0x01 ; transmit character
mov dx, 0x0 ; COM1
int 0x14
ret
;; Update the color_mode variable with a byte from the keyboard ;; Update the color_mode variable with a byte from the keyboard
;; ;;
;; CLOBBERS ;; CLOBBERS