Sylva OS — Agent Guide

x86_64 UEFI hobby OS kernel. C17 boot → C++17 kernel, ELF64 → PE32+ via objcopy.

Build & Run

Command	What
`make`	Build `build/BOOTX64.EFI`
`make run`	QEMU + OVMF, serial → `serial.log`, paused for GDB (`-s -S`)
`make clean`	Always before commit — gnu-efi produces untracked files

boot.c — UEFI entrypoint (efi_main), calls kernel_main()
kernel/main.cpp — extern "C" kernel_main(): init GOP → serial → PMM → heap → idle loop (hlt)
kernel/serial.cpp — UEFI serial protocol wrapper
kernel/memory/pmm.cpp — bitmap + free-list physical page allocator
kernel/memory/heap.cpp — kmalloc/kfree/kcalloc/krealloc (first-fit, coalescing)
graphics/ — GOP framebuffer pixel drawing
fonts/ — Hankaku 8×16 pixel font renderer
gnu-efi/ — git submodule (https://github.com/ncroxon/gnu-efi.git)

uefi_call_wrapper required for all UEFI protocol calls or kernel page-faults
kernel_main must be extern "C" (C→C++ linkage)
QEMU starts paused — connect GDB to :1234 to proceed
No tests, no CI, no lint/formatter config
C17 (boot.c), C++17 (kernel/)
Standards: -ffreestanding -fno-stack-protector -fshort-wchar -mno-red-zone
#define ASM asm volatile in include/common.h
BUILD_INFOS.h is a placeholder for CI