Ada Bare Bones: Difference between revisions
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| [unchecked revision] | [unchecked revision] |
Content added Content deleted
m (→GAS) |
m (Fix a typo, revert indentation for some comments to make the code readable.) |
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.global startup # Make the startup entry point symbol visible to the linker |
.global startup # Make the startup entry point symbol visible to the linker |
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# Set up the Multiboot header (see GRUB docs for details) |
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.set ALIGN, 1<<0 # Align loaded modules on page boundaries |
.set ALIGN, 1<<0 # Align loaded modules on page boundaries |
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.set MEMINFO, 1<<1 # Provide memory map |
.set MEMINFO, 1<<1 # Provide memory map |
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| Line 433: | Line 433: | ||
.long CHECKSUM |
.long CHECKSUM |
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# Reserve initial kernel stack space |
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.set STACKSIZE, 0x4000 # 0x4000 being 16k. |
.set STACKSIZE, 0x4000 # 0x4000 being 16k. |
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.lcomm stack, STACKSIZE # Reserve 16k stack on a doubleword (32bit) boundary |
.lcomm stack, STACKSIZE # Reserve 16k stack on a doubleword (32bit) boundary |
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movl $(stack + STACKSIZE), %esp # Set up the stack |
movl $(stack + STACKSIZE), %esp # Set up the stack |
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# The following saves the contents of the registers as they will likely be |
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# overwritten because main is not our actual entry point, Bare_Bones is. We |
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# will use these 2 symbols inside Bare_Bones. |
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movl %eax, magic # EAX indicates to the OS that it was loaded by a Multiboot-compliant boot |
movl %eax, magic # EAX indicates to the OS that it was loaded by a Multiboot-compliant boot |
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