ZeusWPI/ass_messages
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remove unnecessary instructions

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This commit is contained in:
Tibo Ulens 2021-10-08 14:21:20 +02:00
parent 6f971cf6c7
commit e2747fc424
1 changed files with 10 additions and 10 deletions
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18
messages.asm
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@ -167,7 +167,7 @@ beep:
;; interrupt 0x16, ah=0 returns the read scancode in ah
;; so ah must be reset
mov ah, 0
push ax ; store on stack
mov cx, ax ; save ax into cx temporarily
;; move 182 (0b10 11 011 0) into al
;; bit 7-6 = channel select (2, PC speaker)
@ -196,12 +196,9 @@ beep:
;; mov bx, 50000 ; Pause for duration of note.
;; multiply duration by 3125
pop bx ; pull duration value from stack into bx
push ax ; save ax (contains garbage?)
;; (duration is in cx)
mov ax, 3125
mul bx
mov bx, ax ; move dur * 3125 into bx
pop ax ; restore ax
mul cx ; multiply ax <- ax * cx
;; play note for a certain duration
.pause1:
@ -210,7 +207,7 @@ beep:
dec cx ; count down
jne .pause2 ; if not zero keep counting down
dec bx ; decrement duration counter
dec ax ; decrement duration counter
jne .pause1 ; keep doing that until it is 0
in al, 0x61 ; Preserve previous value
@ -235,7 +232,8 @@ nonewline:
int 0x10
;; Get current cursor position
;; dh = row, dl = col
;; bh already contains page number
;; returns dh = row, dl = col
mov ah, 0x03 ; get cursor position and shape
int 0x10
@ -252,7 +250,9 @@ nonewline:
.noeol:
;; Move cursor forward
inc dl
;; bh already contains page number
;; dh already contains row
inc dl ; go to next col
mov ah, 0x02 ; set cursor position, dh (row) already set, dl (col) updated on prev line
int 0x10