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| author | Joursoir <chat@joursoir.net> | 2022-09-29 10:52:00 +0300 |
|---|---|---|
| committer | Joursoir <chat@joursoir.net> | 2022-10-07 22:18:32 +0300 |
| commit | 9d1dc21b597470a1acb5b512c240c7f27b87b17c (patch) | |
| tree | ab59d7377e63e862e62fd156520f36402994b536 /arch/x86/boot | |
| parent | 387c11b9c8baff0e6f1617d80b95a9bbffcdfdf5 (diff) | |
| download | mfsos-9d1dc21b597470a1acb5b512c240c7f27b87b17c.tar.gz mfsos-9d1dc21b597470a1acb5b512c240c7f27b87b17c.tar.bz2 mfsos-9d1dc21b597470a1acb5b512c240c7f27b87b17c.zip | |
x86/multiboot: add multiboot header
Unfortunately, GNU AS doesn't perform GCC-like preprocessing. So, to
include the multiboot header in the assembly code, we should parse
and format it to GAS-style.
Diffstat (limited to 'arch/x86/boot')
| -rw-r--r-- | arch/x86/boot/multiboot/Makefile | 25 | ||||
| -rw-r--r-- | arch/x86/boot/multiboot/multiboot.s | 11 |
2 files changed, 30 insertions, 6 deletions
diff --git a/arch/x86/boot/multiboot/Makefile b/arch/x86/boot/multiboot/Makefile new file mode 100644 index 0000000..995237d --- /dev/null +++ b/arch/x86/boot/multiboot/Makefile @@ -0,0 +1,25 @@ +# If you want run this makefile immediately, then set environment +# variables (CC, LD, AS, OBJDUMP) to path of your cross-compiler. +# +# The best way to build multiboot header is to run the corresponding +# target in the main Makefile, which is in the root of the +# project (.../path/to/os/Makefile) + +MULTIBOOT_HEADER = $(ARCH_INCLUDE)/multiboot.h +BARE_MULTIBOOT_HEADER = bare_multiboot.h + +.PHONY: all clean + +all: $(BARE_MULTIBOOT_HEADER) + +$(BARE_MULTIBOOT_HEADER): $(MULTIBOOT_HEADER) + $(CC) -E -dM -undef -fsyntax-only $(MULTIBOOT_HEADER) > $(BARE_MULTIBOOT_HEADER) +# Delete all defines that have double underscore + sed -i '/__/d' $(BARE_MULTIBOOT_HEADER) +# Replace "#define" with ".set" on each line + sed -i 's/#define/.set/g' $(BARE_MULTIBOOT_HEADER) +# Put a comma after the macro name + sed -i 's/\>/,/2' $(BARE_MULTIBOOT_HEADER) + +clean: + rm $(BARE_MULTIBOOT_HEADER) diff --git a/arch/x86/boot/multiboot/multiboot.s b/arch/x86/boot/multiboot/multiboot.s index 33e54f1..e6e8c21 100644 --- a/arch/x86/boot/multiboot/multiboot.s +++ b/arch/x86/boot/multiboot/multiboot.s @@ -1,13 +1,12 @@ # https://www.gnu.org/software/grub/manual/multiboot/multiboot.html +.include "bare_multiboot.h" # the file is auto-generated + /* Declare constants for the multiboot header. */ -.set ALIGN, 1 << 0 # align loaded modules on page boundaries -.set MEMINFO, 1 << 1 # provide memory map -.set FLAGS, ALIGN | MEMINFO # this is the Multiboot 'flag' field -.set MAGIC, 0x1BADB002 # 'magic number' lets bootloader find the header -.set CHECKSUM, -(MAGIC + FLAGS) # checksum of above, to prove we are multiboot +.set FLAGS, MULTIBOOT_PAGE_ALIGN | MULTIBOOT_MEMORY_INFO # this is the Multiboot 'flag' field +.set CHECKSUM, -(MULTIBOOT_HEADER_MAGIC + FLAGS) # checksum of above, to prove we are multiboot /* Declare a multiboot header that marks the program as a kernel. @@ -19,7 +18,7 @@ its own section so the header can be forced to be within the first */ .section .multiboot .align 4 -.long MAGIC +.long MULTIBOOT_HEADER_MAGIC .long FLAGS .long CHECKSUM |