use movzx instead of goofy mov word and and mask the upper bits

2024-10-18 07:58:40 -04:00
parent b7e2a8e886
commit d98786072c
1 changed files with 1 additions and 4 deletions
--- a/src/stage2/stage2.nasm
+++ b/src/stage2/stage2.nasm
@@ -235,10 +235,7 @@ ALIGN 4, db 0x90
 PrintCharacter:
    __CDECL16_ENTRY
 .func:
-    mov ax, [bp + 4] ; c
-    mov dx, 0x00ff
-    and ax, dx
-
+    movzx ax, byte [bp + 4]     ; AL = character c
    mov ah, 0x0E                ; INT 0x10, AH=0x0E call
    mov bx, 0x0007              ; BH = page no. BL =Text attribute 0x07 is lightgrey font on black background
    int 0x10                    ; call video interrupt