diff options
Diffstat (limited to 'cpu/i386/start16.S')
| -rw-r--r-- | cpu/i386/start16.S | 46 |
1 files changed, 23 insertions, 23 deletions
diff --git a/cpu/i386/start16.S b/cpu/i386/start16.S index a34642f..239f2ff 100644 --- a/cpu/i386/start16.S +++ b/cpu/i386/start16.S @@ -1,5 +1,5 @@ /* - * U-boot - i386 Startup Code + * U-boot - i386 Startup Code * * Copyright (c) 2002, 2003 Omicron Ceti AB, Daniel Engström <denaiel@omicron.se> * @@ -30,37 +30,37 @@ .section .start16, "ax" .code16 .globl start16 -start16: +start16: /* First we let the BSP do some early initialization * this code have to map the flash to its final position */ mov $board_init16_ret, %bp jmp board_init16 -board_init16_ret: - +board_init16_ret: + /* Turn of cache (this might require a 486-class CPU) */ - movl %cr0, %eax - orl $0x60000000,%eax - movl %eax, %cr0 - wbinvd - + movl %cr0, %eax + orl $0x60000000,%eax + movl %eax, %cr0 + wbinvd + /* load the descriptor tables */ o32 cs lidt idt_ptr -o32 cs lgdt gdt_ptr +o32 cs lgdt gdt_ptr /* Now, we enter protected mode */ - movl %cr0, %eax - orl $1,%eax - movl %eax, %cr0 - + movl %cr0, %eax + orl $1,%eax + movl %eax, %cr0 + /* Flush the prefetch queue */ - jmp ff + jmp ff ff: /* Finally jump to the 32bit initialization code */ - movw $code32start, %ax - movw %ax,%bp + movw $code32start, %ax + movw %ax,%bp o32 cs ljmp *(%bp) /* 48-bit far pointer */ @@ -71,17 +71,17 @@ code32start: idt_ptr: .word 0 /* limit */ .long 0 /* base */ - + gdt_ptr: .word 0x30 /* limit (48 bytes = 6 GDT entries) */ .long BOOT_SEG + gdt /* base */ - /* The GDT table ... + /* The GDT table ... * - * Selector Type + * Selector Type * 0x00 NULL * 0x08 Unused - * 0x10 32bit code + * 0x10 32bit code * 0x18 32bit data/stack * 0x20 16bit code * 0x28 16bit data/stack @@ -100,12 +100,12 @@ gdt: .word 0x0 /* base address = 0 */ .word 0x9300 /* data read/write */ .word 0x00CF /* granularity = 4096, 386 (+5th nibble of limit) */ - + .word 0xFFFF /* 64kb */ .word 0 /* base address = 0 */ .word 0x9b00 /* data read/write */ .word 0x0010 /* granularity = 1 (+5th nibble of limit) */ - + .word 0xFFFF /* 64kb */ .word 0 /* base address = 0 */ .word 0x9300 /* data read/write */ |