From 65c9bf56f597e46bdf9d0acb5c46832a41366db0 Mon Sep 17 00:00:00 2001
From: Thomas Oltmann <thomas.oltmann.hhg@gmail.com>
Date: Thu, 17 Jul 2025 07:09:21 +0200
Subject: [PATCH] Separate BSS section, cleared manually at runtime.

---
 Makefile     | 2 +-
 fernlader.ld | 8 +++++++-
 lboot.S      | 8 +++++++-
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/Makefile b/Makefile
index edd51a3..ccb35cf 100644
--- a/Makefile
+++ b/Makefile
@@ -11,7 +11,7 @@ config.mk: | config.default.mk
 	cp config.default.mk $@
 
 boot.bin: boot.elf
-	objcopy -O binary --only-section=.text boot.elf $@
+	objcopy -O binary -j .text -j .data boot.elf $@
 
 boot.elf: lboot.o loader.o fernlader.ld
 	$(LD) $(LDFLAGS) -o $@ lboot.o loader.o
diff --git a/fernlader.ld b/fernlader.ld
index abcf9ac..4b32b5c 100644
--- a/fernlader.ld
+++ b/fernlader.ld
@@ -6,9 +6,15 @@ SECTIONS {
     .text 0x7C00: {
         lboot.o(.text)
         *(.text, .rodata*)
+    } :all
+    .data : {
         *(.data)
-        *(.bss, COMMON)
         . = ALIGN(4K);
         lboot.o(.data.bootboot)
     } :all
+    _bss_start = .;
+    .bss (NOLOAD) : {
+        *(.bss, COMMON)
+    } :all
+    _bss_end = .;
 }
diff --git a/lboot.S b/lboot.S
index c5977e2..5106227 100644
--- a/lboot.S
+++ b/lboot.S
@@ -57,6 +57,12 @@ _start:     cli
             mov         %ax, %ds
             mov         %ax, %es
 
+            mov         $_bss_start, %di
+            mov         $_bss_end, %cx
+            sub         %di, %cx
+            xor         %al, %al
+            rep         stosb
+
             call        init_com1
 
             mov         $msg_start, %si
@@ -122,7 +128,7 @@ _start:     cli
 
             mov         $msg_long, %si
             call        print
-            jmp         hang // REMOVE ME
+            //jmp         hang // REMOVE ME
             call        long
 
             jmp         hang