From: Jan Beulich <jbeulich@suse.com>
Date: Thu, 7 Apr 2022 06:34:58 +0000 (+0200)
Subject: x86/boot: fold branches in video handling code
X-Git-Tag: archive/raspbian/4.17.0-1+rpi1^2~33^2~774
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=2f576a65a09d98e63e548143825d7a33fa5cff1b;p=xen.git

x86/boot: fold branches in video handling code

Using Jcc to branch around a JMP is necessary only in pre-386 code,
where Jcc is limited to disp8. Use the opposite Jcc directly in two
places. Since it's adjacent, also convert an ORB to TESTB.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
---

diff --git a/xen/arch/x86/boot/video.S b/xen/arch/x86/boot/video.S
index 822d6d9cf1..b5af93dbc5 100644
--- a/xen/arch/x86/boot/video.S
+++ b/xen/arch/x86/boot/video.S
@@ -332,8 +332,7 @@ lment:  movb    $0, (%di)
         cmpw    $0x656d, (%si)          # 'me'
         jnz     lmhx
         cmpw    $0x756e, 2(%si)         # 'nu'
-        jnz     lmhx
-        jmp     listm
+        jz      listm
 
 lmhx:   xorw    %bx, %bx                # Else => mode ID in hex
 lmhex:  lodsb
@@ -401,10 +400,8 @@ mode_set:
         cmpb    $VIDEO_FIRST_VESA>>8, %ah
         jnc     check_vesa
 
-        orb     %ah, %ah
-        jnz     setbad
-
-        jmp     setmenu
+        testb   %ah, %ah
+        jz      setmenu
 
 setbad: clc
         ret