From 46cd7e026b04d477261b7e06de1005ae16465585 Mon Sep 17 00:00:00 2001
From: "Chloe M." <chloe@aptel.org>
Date: Thu, 20 Aug 2026 11:08:38 +0000
Subject: boot/amd64: mbr: Jump to stage 2

Signed-off-by: Chloe M. <chloe@aptel.org>
---
 boot/arch/amd64/mbr/mbr.S | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

(limited to 'boot/arch/amd64/mbr')

diff --git a/boot/arch/amd64/mbr/mbr.S b/boot/arch/amd64/mbr/mbr.S
index 1ce1da1..5d876c2 100644
--- a/boot/arch/amd64/mbr/mbr.S
+++ b/boot/arch/amd64/mbr/mbr.S
@@ -56,12 +56,22 @@ reloc:
 
     /* Get stage2 */
     call find_stage2
-1:  cli
-    hlt
-    jmp 1b
+
+    /* Obtain the data offset */
+    mov $BOOT_SEG, %ax
+    mov %ax, %ds
+    add $40, %si
+    movw (%si), %ax
+
+    /* Jump to stage 2 */
+    pushw $BOOT_SEG
+    pushw %ax
+    lret
 
 /*
  * Locate stage2 on the disk
+ *
+ * Stage 2 data descriptor is returned in %SI
  */
 find_stage2:
     push %ds
@@ -98,12 +108,11 @@ find_stage2:
     rep cmpsb
     jne 1b
 
+    mov %dx, %si
     stc
     pop %es
     pop %ds
     jnc .not_found
-
-    /* TODO: On found, return the offset to the data in %CX */
     ret
 .not_found:
     pop %ds
@@ -124,7 +133,6 @@ find_stage2:
     hlt
     jmp 1b
 
-
 /*
  * Read sectors from the disk
  */
-- 
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