From: John Tsiombikas <nuclear@member.fsf.org>
Date: Sat, 30 Sep 2023 19:05:18 +0000 (+0300)
Subject: moving to 2MB, need to modify ldscript for vma/lma
X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?a=commitdiff_plain;h=c213ae83bf00aefb9526238658e6739ee9a71187;p=com32

moving to 2MB, need to modify ldscript for vma/lma
---

diff --git a/com32.ld b/com32.ld
index 04c9f88..4771389 100644
--- a/com32.ld
+++ b/com32.ld
@@ -4,10 +4,10 @@ ENTRY(_start)
 SECTIONS {
 	/* loader starts at <seg>:100h */
 	. = 0x100;
-	.loader : {
-		* (.loader);
-		* (.ldrtext);
-	}
+	.loader : { * (.loader); }
+
+	. = ALIGN(4);
+	_ldr_main_start = .;
 
 	/* main program will be moved to 2MB by the loader */
 	. = 2M;
diff --git a/src/loader.asm b/src/loader.asm
index 6b4f288..18bd286 100644
--- a/src/loader.asm
+++ b/src/loader.asm
@@ -1,7 +1,10 @@
 	section .loader
 
 	extern startup
-	extern tmpsegbase
+
+	extern _ldr_main_start
+	extern _main_start
+	extern _main_size
 
 	[bits 16]
 	global _start
@@ -34,7 +37,6 @@ _start:
 	xor eax, eax
 	mov ax, cs
 	shl eax, 4
-	mov [tmpsegbase], eax	; save segment base
 	add eax, gdt
 	mov [gdt_base], eax
 
@@ -64,13 +66,23 @@ _start:
 	[bits 32]
 .pm:	mov ax, 20h	; tmp data selector
 	mov ds, ax
-	mov ss, ax
 	mov ax, 10h	; dest data selector
 	mov es, ax
 
+	; copy main program high
+	cld
+	mov esi, _ldr_main_start
+	mov edi, _main_start
+	lea ecx, [_main_size + 3]
+	shr ecx, 2
+	rep movsd
+
+	mov ax, 10h
+	mov ds, ax
+	mov ss, ax
 	mov esp, 200000h
 
-	call startup
+	call 8:startup
 
 	; return to real mode
 	jmp 28h:.rm
diff --git a/src/startup.asm b/src/startup.asm
index 8c2b643..99cbf6c 100644
--- a/src/startup.asm
+++ b/src/startup.asm
@@ -1,14 +1,10 @@
 	bits 32
-	section .ldrtext
+	section .text
 
 	global startup
 startup:
 	mov ebx, 0xb8000
-	sub ebx, [tmpsegbase]
 	mov byte [ebx], '@'
 	ret
 
-	global tmpsegbase
-tmpsegbase dd 0
-
 ; vi:set ts=8 sts=8 sw=8 ft=nasm: