diff options
Diffstat (limited to 'boot.s')
| -rw-r--r-- | boot.s | 57 |
1 files changed, 0 insertions, 57 deletions
@@ -1,57 +0,0 @@ -/* Multiboot header dark magic, do not touch */ -.set ALIGN, 1<<0 -.set MEMINFO, 1<<1 -.set FLAGS, ALIGN | MEMINFO -.set MAGIC, 0x1BADB002 -.set CHECKSUM, -(MAGIC + FLAGS) - -.section .multiboot -.align 4 -.long MAGIC -.long FLAGS -.long CHECKSUM - -/* Multiboot does not define the esp/stack, create the stack ourselves */ -.section bss -/* Stack on x86 must be 16-byte aligned by the System V ABI standard */ -.align 16 -/* Create a symbol at the bottom, allocate 16KiB, then finally create a symbol at the top */ -stack_bottom: -.skip 16384 -stack_top: - -/* _start is the entrypoint */ -.section text -.global _start -.type _start, @function -_start: - /* we are in 32bit protected mode - interrupts disabled, paging disabled - kernel has full control over cpu */ - - /* setup the stack, point to the top becausei t grows downwrad on x86 for som e reason */ - mov $stack_top, %esp - - /* here we need to init crucial processor state. - load the gdt, enable pages, init isa extensions/floating point instructions and stuff - for now just dont do anything we'll add that later */ - - /* enter the high level kernel - ABI says we need 16-byte alignment here, we aligned that before and pushed a multiple of 16 bits (zero) so we fine - but i will realign for good measure anyway */ - .align 16 - call kernel_main - - /* if nothing left then just infinite loop */ - /* - 1. disable interrupts with cli/clear interrupts - 2. wait for next interrupt with hlt. because they disabled this will just lockup the ocmputer - 3. justincase it wakes up just jmp back to the hlt instruction - */ - cli -1: hlt - jmp 1b - -/* set the size of the _start symbol to the current location (.) minus it's _start -for debugging stuff */ -.size _start, . - _start |