From da6f981a6a1a78b0f6c2093b994109fac1424f97 Mon Sep 17 00:00:00 2001
From: pantonshire <tom@tomandtally.co.uk>
Date: Sat, 26 Jul 2025 18:01:59 +0100
Subject: [PATCH] move gdt, use fixed addr

---
 include/layout.s    | 2 +-
 stage_2/main.s      | 6 ++----
 stage_3/src/main.rs | 2 +-
 3 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/include/layout.s b/include/layout.s
index b4c04ed..21666c4 100644
--- a/include/layout.s
+++ b/include/layout.s
@@ -9,7 +9,7 @@
 %define S2_DATA        S2_LOAD_ADDR
 %define S2_ENTRYPOINT  (S2_DATA_ADDR + S2_DATA_LEN)
 
-%define GDT_ADDR       0xc000
+%define GDT_FLAT_ADDR  0xe000
 %define S3_LOAD_ADDR   0x10000
 
 ; %define MEMMAP          0x6a00
diff --git a/stage_2/main.s b/stage_2/main.s
index 2341436..f4e490f 100644
--- a/stage_2/main.s
+++ b/stage_2/main.s
@@ -39,7 +39,7 @@ s2_main:
   ; Copy the GDT
   mov cx, GDT_FLAT_LEN
   mov si, gdt_flat
-  mov di, GDT_ADDR
+  mov di, GDT_FLAT_ADDR
   rep movsb
 
   ; Ensure interrupts are definitely disabled.
@@ -86,9 +86,7 @@ section .s3_data
 
 gdt_flat_slice:
   dw GDT_FLAT_LEN
-  dd gdt_flat
-
-global gdt_flat_slice
+  dd GDT_FLAT_ADDR
 
 ; Segment descriptor layout
 ; | Range (bits) | Field         |
diff --git a/stage_3/src/main.rs b/stage_3/src/main.rs
index 15569fe..98f3ed0 100644
--- a/stage_3/src/main.rs
+++ b/stage_3/src/main.rs
@@ -35,7 +35,7 @@ pub extern "C" fn _start() -> ! {
         com::try_com1_init();
     }
 
-    let gdt_ptr = ptr::with_exposed_provenance::<u64>(0xc000);
+    let gdt_ptr = ptr::with_exposed_provenance::<u64>(0xe000);
     let gdt_slice = unsafe { slice::from_raw_parts(gdt_ptr, 4) };
 
     vga_println!("hello from rust :)");