1 changed files with 3 additions and 2 deletions
--- a/ponydos.asm
+++ b/ponydos.asm
@ -129,7 +129,7 @@ mainloop:
 ; in:
 ;  bx = width of input buffer
 ;  cx = width of rectangle
-;  dx = height of rectangle (must be at least 1)
+;  dx = height of rectangle
 ;  ds:si = beginning of source data
 ;  di = X
 ;  bp = Y
@ -153,11 +153,12 @@ draw_rect:

 	; Convert widths to bytes
 	shl bx, 1
+	shl cx, 1

 	.loop:
 		; Copy a row
 		pusha
-		rep movsw
+		rep movsb
 		popa

 		; Move to the next row in the input buffer