From 7356a83a44fb0afa9e17cd09d62699df82799282 Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Wed, 3 Jan 2024 17:05:33 +0200
Subject: [PATCH] Bootloader: Optimize some unnecessary branches on carry
 add/sub

---
 bootloader/bios/disk.S        | 10 +++-------
 bootloader/bios/framebuffer.S |  3 +--
 2 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/bootloader/bios/disk.S b/bootloader/bios/disk.S
index bdba2cba..1b49c4d4 100644
--- a/bootloader/bios/disk.S
+++ b/bootloader/bios/disk.S
@@ -389,10 +389,8 @@ find_root_partition:
 
 	# increment 8 byte entry array lba
 	incl 0(%esp)
-	jnc .find_root_partition_no_overflow
-	incl 4(%esp)
+	adcl $0, 4(%esp)
 
- .find_root_partition_no_overflow:
 	# loop to read next section if entries remaining
 	cmpl $0, 12(%esp)
 	jnz .find_root_partition_read_entry_section
@@ -416,12 +414,10 @@ find_root_partition:
 
 	# ebx:eax -= first lba - 1
 	subl (root_partition_entry + 36), %ebx
-	movl (root_partition_entry + 32), %ecx;
+	movl (root_partition_entry + 32), %ecx
 	decl %ecx
 	subl %ecx, %eax
-	jnc .find_root_partition_count_sub_no_carry
-	decl %ebx
- .find_root_partition_count_sub_no_carry:
+	sbbl $0, %ebx
  	
 	# ecx: min(partition count, 0xFFFFFFFF)
 	movl $0xFFFFFFFF, %edx
diff --git a/bootloader/bios/framebuffer.S b/bootloader/bios/framebuffer.S
index ad2fbe8c..3ff46c0f 100644
--- a/bootloader/bios/framebuffer.S
+++ b/bootloader/bios/framebuffer.S
@@ -95,8 +95,7 @@ vesa_find_video_mode:
 	cmpw $0x0200, (vesa_info_buffer + 0x04)
 	jb .vesa_unsupported_version
 
-	movl $(vesa_info_buffer + 0x0E), %esi
-	movl (%esi), %esi
+	movl (vesa_info_buffer + 0x0E), %esi
  .vesa_find_video_mode_loop_modes:
 	cmpw $0xFFFF, (%esi)
 	je .vesa_find_video_mode_loop_modes_done