From 8403d77a1811359d1af51adb1b6494de60da8c1b Mon Sep 17 00:00:00 2001
From: Colin Finck <colin@reactos.org>
Date: Sun, 22 Mar 2009 23:36:48 +0000
Subject: [PATCH] - If we determine that the keyboard buffer is full, only call
 INT 16h,0 once without checking again whether the buffer is free afterwards  
 Fixes bug #4264 - Get rid of another procedure for getting a character, can
 be replaced with two instructions in the only place where this procedure was
 called See issue #4264 for more details.

svn path=/trunk/; revision=40176
---
 reactos/boot/freeldr/bootsect/isoboot.asm | 28 ++++-------------------
 1 file changed, 5 insertions(+), 23 deletions(-)

diff --git a/reactos/boot/freeldr/bootsect/isoboot.asm b/reactos/boot/freeldr/bootsect/isoboot.asm
index 0c97f4236ea..054fc5bee78 100644
--- a/reactos/boot/freeldr/bootsect/isoboot.asm
+++ b/reactos/boot/freeldr/bootsect/isoboot.asm
@@ -898,41 +898,23 @@ kaboom:
 	sti
 	mov	si, err_bootfailed
 	call	writestr
-	call	getchar
+	xor	ax, ax		; Wait for keypress
+	int	16h
 	cli
 	mov	word [BIOS_magic], 0	; Cold reboot
 	jmp	0F000h:0FFF0h		; Reset vector address
 
-getchar:
-.again:
-	mov	ah, 1		; Poll keyboard
-	int	16h
-	jz	.again
-.kbd:
-	xor	ax, ax		; Get keyboard input
-	int	16h
-.func_key:
-	ret
-
 
 ;
 ; pollchar_and_empty: check if we have an input character pending (ZF = 0) and empty the input buffer afterwards
 ;
 pollchar_and_empty:
 	pushad
-	mov ah, 1		; Poll keyboard
+	mov ah, 1		; Did the user press a key?
 	int 16h
-	jz	.end
-.empty_buffer:
-	mov ah, 0		; Read from keyboard
+	jz	.end		; No, then we're done
+	mov ah, 0		; Otherwise empty the buffer by reading it
 	int 16h
-	
-	mov ah, 1		; Poll keyboard again
-	int 16h
-	jz	.buffer_emptied
-	jmp .empty_buffer
-.buffer_emptied:
-	and ax, ax	; ZF = 0
 .end:
 	popad
 	ret