8c44d12357
Boots under QEMU on all three ISAs from one clang build: - shared C core (kmain, console) calls a small per-arch contract (arch.h) - per-arch asm entry + trap/vector table + UART driver - parallel Makefile (make -j), 'make run-<arch>', 'make sizes' M1 = boot, UART up, trap vector installed, banner from kmain().
28 lines
667 B
ArmAsm
28 lines
667 B
ArmAsm
# boot.S (x86, i386) — multiboot header + entry.
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# The Multiboot1 header lets QEMU -kernel (and GRUB) load us directly.
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# We set a stack and call kmain(). Irreducible asm part for x86.
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.set MB_MAGIC, 0x1BADB002
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.set MB_FLAGS, 0x0
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.set MB_CHECKSUM, -(MB_MAGIC + MB_FLAGS)
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.section .multiboot, "a"
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.align 4
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.long MB_MAGIC
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.long MB_FLAGS
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.long MB_CHECKSUM
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.section .bss
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.align 16
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stack_bottom:
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.skip 0x4000 # 16 KiB stack
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stack_top:
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.section .text.boot
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.globl _start
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.type _start, @function
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_start:
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mov $stack_top, %esp # set up the stack
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call kmain
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1: hlt # kmain shouldn't return; if it does, halt
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jmp 1b
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