ZeusWPI/ass_messages
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restore functioning code

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This commit is contained in:
Tibo 2021-10-07 19:56:55 +02:00
parent 331da168b4
commit 26c71359e9
1 changed files with 16 additions and 16 deletions
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32
messages.asm
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@ -6,7 +6,7 @@ HEIGHT equ 0x18 ; 24
VIDEO_MODE equ 0x3 ; 80x25 screen, text mode
PIT_MODECOMMAND_PORT equ 0x43 ; programmable interval timer mode/command port (used for speaker)
PIT_CH2_DATA_PORT equ 0x42 ; PIT channel 2 data port
PIT_CH2_DATA_PORT equ 0x42 ; PIT channel 2 data port
;; see http://www.ctyme.com/intr/int-10.htm for interrupts
@ -36,9 +36,9 @@ mov sp, 0x2000 ; initialise stack pointer
;; 1 1 8
;; initialise serial port
mov ah, 0x0 ; initialise UART
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
mov dx, 0x0 ; COM1
int 0x14
;; Use color mode
@ -119,7 +119,7 @@ int 0x10
;; - ax
;; - bl
change_color_mode:
call readbyte ; get byte from keyboard (in al)
call readbyte ; get byte from keyboard (in al)
mov [color_mode], al ; store byte in color_mode variable
jmp compare_virtual_and_jump
@ -159,7 +159,7 @@ newline:
beep:
call read_duration ; get duration from keyboard (in al)
mov ah, 0
push ax ; store on stack
push ax ; store on stack
;; move 182 (0b10 11 011 0) into al
;; bit 7-6 = channel select (2, PC speaker)
@ -175,15 +175,15 @@ beep:
sal ax, 5 ; multiply by 32
add ax, 1140
out PIT_CH2_DATA_PORT, al ; Output low byte.
out PIT_CH2_DATA_PORT, al ; Output low byte.
mov al, ah
out PIT_CH2_DATA_PORT, al ; Output high byte
out PIT_CH2_DATA_PORT, al ; Output high byte
;; Port 0x61 does a whole lot but only the bottom 2 bits are relevant here
;; (speaker enable and speaker input select)
in al, 0x61 ; Preserve previous value
in al, 0x61 ; Preserve previous value
or al, 00000011b ; Set bits 1 and 0 (enable speaker, input = channel 2)
out 0x61, al ; Send new value
out 0x61, al ; Send new value
;; mov bx, 50000 ; Pause for duration of note.
@ -199,13 +199,13 @@ beep:
.pause1:
mov ecx, 65535
.pause2:
dec cx ; count down
dec cx ; count down
jne .pause2 ; if not zero keep counting down
dec bx ; decrement duration counter
dec bx ; decrement duration counter
jne .pause1 ; keep doing that until it is 0
in al, 0x61 ; Preserve previous value
in al, 0x61 ; Preserve previous value
and al, 11111100b ; Clear bits 1 and 0 (disable speaker, clear channel select)
out 0x61, al ; Send new value
@ -220,10 +220,10 @@ beep:
;; - dx
nonewline:
;; Write character
mov ah, 0x09 ; write character with attribute
mov bh, 0x00 ; page number
mov ah, 0x09 ; write character with attribute
mov bh, 0x00 ; page number
mov bl, [color_mode] ; BIOS colour code
mov cx, 0x01 ; amount of times to print character
mov cx, 0x01 ; amount of times to print character
int 0x10
;; Get current cursor position
@ -277,7 +277,7 @@ readbyte:
int 0x16
;; Read character is in al
sub al, 'a' ; Normalise
sub al, 'a' ; Normalise
mov bl, al
shl bl, 0x04 ; First character is upper 4 bits