:: commit 5e023bce3d827dfeacab2af7c12cc75eb232f0c5
stage1: Misc improvements
diff --git a/stage1/cd/bootsect.asm b/stage1/cd/bootsect.asm
index 083d2e35..47f4bfc6 100644
--- a/stage1/cd/bootsect.asm
+++ b/stage1/cd/bootsect.asm
@@ -1,9 +1,5 @@
-BITS 16
-ORG 0x7C00
-
-%define STAGE2_LOCATION 0x60000
-%define DECOMPRESSOR_LOCATION 0x70000
-%define BOOT_FROM_CD 2
+org 0x7c00
+bits 16
jmp skip_bpb
nop
@@ -25,42 +21,31 @@ skip_bpb:
cld
jmp 0x0000:.initialise_cs
.initialise_cs:
- xor ax, ax
- mov ds, ax
- mov es, ax
- mov ss, ax
- mov sp, 0x7C00
+ xor si, si
+ mov ds, si
+ mov es, si
+ mov ss, si
+ mov sp, 0x7c00
sti
; int 13h?
mov ah, 0x41
- mov bx, 0x55AA
+ mov bx, 0x55aa
int 0x13
- jc err
- cmp bx, 0xAA55
- jne err
-
- mov esp, 0x7C00
+ jc err.0
+ cmp bx, 0xaa55
+ jne err.1
; --- Load the decompressor ---
mov eax, dword [bi_boot_LBA]
- add eax, DEC_LBA_OFFSET
- mov ecx, DEC_LBA_COUNT
+ add eax, 1
+ mov ecx, stage2.fullsize / 2048
; DECOMPRESSOR_LOCATION = 0x70000 = 0x7000:0x0000
- mov si, 0x7000
- xor di, di
+ push 0x7000
+ pop es
+ xor bx, bx
call read_2k_sectors
- jc err
-
- ; --- Load the stage2.bin.gz ---
- mov eax, dword [bi_boot_LBA]
- add eax, STAGE2_LBA_OFFSET
- mov ecx, STAGE2_LBA_COUNT
- ; STAGE2_LOCATION = 0x60000 = 0x6000:0x0000
- mov si, 0x6000
- xor di, di
- call read_2k_sectors
- jc err
+ jc err.2
; Enable GDT
lgdt [gdt]
@@ -72,13 +57,25 @@ skip_bpb:
jmp 0x08:pmode
err:
- hlt
- jmp err
+ .2:
+ inc si
+ .1:
+ inc si
+ .0:
+ add si, '0' | (0x4f << 8)
+
+ push 0xb800
+ pop es
+ mov word [es:0], si
+
+ sti
+ .h: hlt
+ jmp .h
%include 'read_2k_sectors.asm'
%include '../gdt.asm'
-BITS 32
+bits 32
pmode:
mov eax, 0x10
mov ds, ax
@@ -88,27 +85,22 @@ pmode:
mov ss, ax
; Time to handle control over to the decompressor
- push BOOT_FROM_CD
- and edx, 0xFF
+ push 2
+ and edx, 0xff
push edx ; Boot drive
- push STAGE2_SIZE
- push STAGE2_LOCATION
- call DECOMPRESSOR_LOCATION
- hlt
-
-%define FILEPOS ($-$$)
-%define UPPER2K ((FILEPOS+2047) & ~2047)
-%define ALIGN2K times UPPER2K - FILEPOS db 0
+ push stage2.size
+ push (stage2 - decompressor) + 0x70000
+ call 0x70000
; Align stage2 to 2K ON DISK
-ALIGN2K
-DEC_LBA_OFFSET equ ($-$$)/2048
+times 2048-($-$$) db 0
+decompressor:
incbin '../../build/decompressor/decompressor.bin'
-ALIGN2K
-STAGE2_START equ $-$$
-STAGE2_LBA_OFFSET equ STAGE2_START/2048
-DEC_LBA_COUNT equ STAGE2_LBA_OFFSET - DEC_LBA_OFFSET
+align 16
+stage2:
incbin '../../build/stage23-bios/stage2.bin.gz'
-STAGE2_SIZE equ ($-$$) - STAGE2_START
-STAGE2_LBA_COUNT equ (2047 + $-$$)/2048
+.size: equ $ - stage2
+
+times ((($-$$)+2047) & ~2047)-($-$$) db 0
+.fullsize: equ $ - decompressor
diff --git a/stage1/cd/read_2k_sectors.asm b/stage1/cd/read_2k_sectors.asm
index 7ebd0ba5..14090fe7 100644
--- a/stage1/cd/read_2k_sectors.asm
+++ b/stage1/cd/read_2k_sectors.asm
@@ -1,4 +1,4 @@
-BITS 16
+bits 16
; --- Read sectors from disk ---
; IN:
@@ -6,8 +6,8 @@ BITS 16
; cx <- number of 2k sectors
; dl <- drive number
; ds <- ZERO
-; di <- buffer offset
-; si <- buffer segment
+; bx <- buffer offset
+; es <- buffer segment
; OUT:
; Carry if error
@@ -25,8 +25,8 @@ read_2k_sectors:
pusha
mov dword [dapack_LBA], eax
mov word [dapack_nblocks], cx
- mov word [dapack_offset], di
- mov word [dapack_segment], si
+ mov word [dapack_offset], bx
+ mov word [dapack_segment], es
mov ah, 0x42
mov si, dapack
diff --git a/stage1/hdd/bootsect.asm b/stage1/hdd/bootsect.asm
index 23e55436..5a341aef 100644
--- a/stage1/hdd/bootsect.asm
+++ b/stage1/hdd/bootsect.asm
@@ -16,10 +16,10 @@ start:
cld
jmp 0x0000:.initialise_cs
.initialise_cs:
- xor bx, bx
- mov ds, bx
- mov es, bx
- mov ss, bx
+ xor si, si
+ mov ds, si
+ mov es, si
+ mov ss, si
mov sp, 0x7c00
sti
@@ -27,25 +27,20 @@ start:
; So if the value the BIOS passed is <0x80, just assume it has passed
; an incorrect value.
cmp dl, 0x80
- jb floppy_err
+ jb err.0
; Values above 0x8f are dubious so we assume we weren't booted properly
; for those either
cmp dl, 0x8f
- ja hdd_err
+ ja err.1
.continue:
; Make sure int 13h extensions are supported
mov ah, 0x41
mov bx, 0x55aa
int 0x13
- jc err
+ jc err.2
cmp bx, 0xaa55
- jne err
-
- ; If int 13h extensions are supported, then we are definitely running on
- ; a 386+. We have no idea whether the upper 16 bits of esp are cleared, so
- ; make sure that is the case now.
- mov esp, 0x7c00
+ jne err.3
push 0x7000
pop es
@@ -56,13 +51,13 @@ start:
xor ecx, ecx
mov cx, word [di-4]
call read_sectors
- jc err
+ jc err.4
mov eax, dword [di+8]
mov ebp, dword [di+12]
add bx, cx
mov cx, word [di-2]
call read_sectors
- jc err
+ jc err.5
lgdt [gdt]
@@ -82,20 +77,27 @@ times 6 db 0
%include '../gdt.asm'
err:
+ .5:
+ inc si
+ .4:
+ inc si
+ .3:
+ inc si
+ .2:
+ inc si
+ .1:
+ inc si
+ .0:
+ add si, '0' | (0x4f << 8)
+
push 0xb800
pop es
- mov dword [es:0], eax
+ mov word [es:0], si
+
+ sti
.h: hlt
jmp .h
-floppy_err:
- mov eax, 'F ! '
- jmp err
-
-hdd_err:
- mov eax, 'H ! '
- jmp err
-
bits 32
vector:
mov eax, 0x10
diff --git a/stage1/pxe/bootsect.asm b/stage1/pxe/bootsect.asm
index a2f8e638..f0d94be4 100644
--- a/stage1/pxe/bootsect.asm
+++ b/stage1/pxe/bootsect.asm
@@ -2,6 +2,8 @@ org 0x7c00
bits 16
start:
+ cli
+ cld
jmp 0x0000:.initialise_cs
.initialise_cs:
xor ax, ax
@@ -9,10 +11,8 @@ start:
mov es, ax
mov ss, ax
mov sp, 0x7c00
- sti
- lgdt [gdt]
- cli
+ lgdt [gdt]
mov eax, cr0
bts ax, 0
@@ -21,7 +21,7 @@ start:
jmp 0x08:.mode32
bits 32
.mode32:
- mov ax, 0x10
+ mov eax, 0x10
mov ds, ax
mov es, ax
mov fs, ax
@@ -42,12 +42,6 @@ start:
call 0x70000
-bits 16
-
-err:
- hlt
- jmp err
-
; Includes
%include '../gdt.asm'
