:: commit b16f63458d09073aec2ec178014160bd4a91ae04
Shuffle around memory layout of bootloader
diff --git a/src/bootsect/bootsect.asm b/src/bootsect/bootsect.asm
index b7404f15..6430c6b6 100644
--- a/src/bootsect/bootsect.asm
+++ b/src/bootsect/bootsect.asm
@@ -15,7 +15,7 @@ start:
mov fs, ax
mov gs, ax
mov ss, ax
- mov sp, 0xfff0
+ mov esp, 0x4000
sti
; Some BIOSes don't pass the correct boot drive number,
@@ -39,12 +39,12 @@ start:
mov si, LoadingMsg
call simple_print
- ; ****************** Load stage 2 ******************
+ ; ****************** Load stage 1.5 ******************
- mov si, Stage2Msg
+ mov si, Stage15Msg
call simple_print
- mov eax, dword [stage2_sector]
+ mov eax, dword [stage15_sector]
mov ebx, 0x7e00
mov ecx, 1
call read_sectors
@@ -73,7 +73,7 @@ halt:
; Data
LoadingMsg db 0x0D, 0x0A, 'Limine', 0x0D, 0x0A, 0x0A, 0x00
-Stage2Msg db 'Loading stage2...', 0x00
+Stage15Msg db 'Loading stage 1.5...', 0x00
ErrReadDiskMsg db 0x0D, 0x0A, 'Disk read error, system halted', 0x00
ErrEnableA20Msg db 0x0D, 0x0A, 'A20 enable error, system halted', 0x00
DoneMsg db ' DONE', 0x0D, 0x0A, 0x00
@@ -87,7 +87,7 @@ times 6 db 0
%include 'disk.inc'
times 0x1b0-($-$$) db 0
-stage2_sector: dd 1
+stage15_sector: dd 1
times 0x1b8-($-$$) db 0
times 510-($-$$) db 0
@@ -97,9 +97,9 @@ dw 0xaa55
stage15:
push es
- push 0x6000
+ push 0x7000
pop es
- mov eax, dword [stage2_sector]
+ mov eax, dword [stage15_sector]
inc eax
xor ebx, ebx
mov ecx, 62
@@ -132,9 +132,9 @@ stage15:
push edx
push stage2.size
- push (stage2 - 0x8000) + 0x60000
+ push (stage2 - 0x8000) + 0x70000
- call 0x60000
+ call 0x70000
bits 16
%include 'a20_enabler.inc'
diff --git a/src/bootsect/disk.inc b/src/bootsect/disk.inc
index c278648f..ecb2acaa 100644
--- a/src/bootsect/disk.inc
+++ b/src/bootsect/disk.inc
@@ -7,41 +7,44 @@
; DL = Drive number
; ES = Buffer segment
; BX = Buffer offset
+; CX = Sectors count
; OUT:
; Carry if error
-read_sector:
- push eax
- push ebx
- push ecx
- push edx
- push esi
- push edi
+read_sectors:
+ pusha
push es
pop word [.target_segment]
mov word [.target_offset], bx
mov dword [.lba_address_low], eax
- xor esi, esi
- mov si, .da_struct
+ mov word [.countdown], cx
+
+ .loop:
+ mov esi, .da_struct
mov ah, 0x42
clc
int 0x13
+ jc .done
+
+ add word [.target_offset], 512
+ inc dword [.lba_address_low]
+
+ dec word [.countdown]
+ jnz .loop
.done:
- pop edi
- pop esi
- pop edx
- pop ecx
- pop ebx
- pop eax
+ popa
ret
+align 2
+ .countdown: dw 0
+
align 4
-.da_struct:
+ .da_struct:
.packet_size db 16
.unused db 0
.count dw 1
@@ -49,71 +52,3 @@ align 4
.target_segment dw 0
.lba_address_low dd 0
.lba_address_high dd 0
-
-; ********************************************
-; Reads multiple LBA addressed sectors
-; ********************************************
-
-; IN:
-; EAX = LBA starting sector
-; DL = Drive number
-; ES = Buffer segment
-; EBX = Buffer offset
-; ECX = Sectors count
-
-; OUT:
-; Carry if error
-
-%define TEMP_BUFFER_SEG 0x7000
-%define BYTES_PER_SECT 512
-
-read_sectors:
- push eax ; Save GPRs
- push ebx
- push ecx
- push edx
- push esi
- push edi
-
- .loop:
- push es
- push ebx
-
- mov bx, TEMP_BUFFER_SEG
- mov es, bx
- xor bx, bx
-
- call read_sector
-
- pop ebx
- pop es
-
- jc .done
-
- push ds
-
- mov si, TEMP_BUFFER_SEG
- mov ds, si
- mov edi, ebx
- xor esi, esi
-
- push ecx
- mov ecx, BYTES_PER_SECT
- a32 o32 rep movsb
- pop ecx
-
- pop ds
-
- inc eax
- add ebx, BYTES_PER_SECT
-
- loop .loop
-
- .done:
- pop edi
- pop esi
- pop edx
- pop ecx
- pop ebx
- pop eax
- ret
diff --git a/src/bootsect/gdt.inc b/src/bootsect/gdt.inc
index 9df929b1..b6a63439 100644
--- a/src/bootsect/gdt.inc
+++ b/src/bootsect/gdt.inc
@@ -2,7 +2,7 @@ load_gdt:
pusha
push es
push ds
- push 0x7000
+ push 0x7ff0
pop es
xor di, di
push 0
@@ -19,7 +19,7 @@ load_gdt:
GDT:
dw .GDTEnd - .GDTStart - 1 ; GDT size
-dd 0x70000 ; GDT start
+dd 0x7ff00 ; GDT start
.GDTStart:
diff --git a/src/decompressor/linker.ld b/src/decompressor/linker.ld
index baf1f0de..12b58ef4 100644
--- a/src/decompressor/linker.ld
+++ b/src/decompressor/linker.ld
@@ -3,7 +3,7 @@ ENTRY(main)
SECTIONS
{
- . = 0x60000;
+ . = 0x70000;
.text : {
KEEP(*(.entry*))
diff --git a/src/decompressor/main.c b/src/decompressor/main.c
index e6bc3841..c097769a 100644
--- a/src/decompressor/main.c
+++ b/src/decompressor/main.c
@@ -22,9 +22,8 @@ ASM_BASIC(
__attribute__((noreturn))
void main(uint8_t *compressed_stage2, size_t stage2_size, uint8_t boot_drive) {
- // The decompressor should decompress compressed_stage2 to address 0x500.
- // For now, just copy it over as it is not compressed. TODO: implement decompressor.
- volatile uint8_t *dest = (volatile uint8_t *)0x500;
+ // The decompressor should decompress compressed_stage2 to address 0x4000.
+ volatile uint8_t *dest = (volatile uint8_t *)0x4000;
tinf_gzip_uncompress(dest, compressed_stage2, stage2_size);
diff --git a/src/lib/blib.c b/src/lib/blib.c
index 98ef721a..6cbd9ef9 100644
--- a/src/lib/blib.c
+++ b/src/lib/blib.c
@@ -45,8 +45,9 @@ __attribute__((noreturn)) void panic(const char *fmt, ...) {
}
}
-static size_t bump_allocator_base = 0x10000;
-#define BUMP_ALLOCATOR_LIMIT ((size_t)0x70000)
+extern symbol bss_end;
+static size_t bump_allocator_base = (size_t)bss_end;
+#define BUMP_ALLOCATOR_LIMIT ((size_t)0x7ff00)
void brewind(size_t count) {
bump_allocator_base -= count;
diff --git a/src/lib/real.asm b/src/lib/real.asm
index 5b815aa6..ee98ced2 100644
--- a/src/lib/real.asm
+++ b/src/lib/real.asm
@@ -1,4 +1,4 @@
-section .text
+section .realmode
global rm_int
rm_int:
diff --git a/src/lib/sleep.asm b/src/lib/sleep.asm
index 9f0bcef5..c0463e32 100644
--- a/src/lib/sleep.asm
+++ b/src/lib/sleep.asm
@@ -1,4 +1,4 @@
-section .text
+section .realmode
int_08_ticks_counter: dd 0
diff --git a/src/linker.ld b/src/linker.ld
index f9f0057f..7f7ddf0d 100644
--- a/src/linker.ld
+++ b/src/linker.ld
@@ -3,10 +3,11 @@ ENTRY(main)
SECTIONS
{
- . = 0x500;
+ . = 0x4000;
.text : {
KEEP(*(.entry*))
+ KEEP(*(.realmode*))
*(.text*)
}
