# arch.mk - Target architecture settings shared by every userspace Makefile
# Copyright (c) 2026 Daniel Hammer
#
# Included by programs/GNUmakefile and the per-program/per-library
# Makefiles. Pass ARCH=aarch64 (the top-level build does) to build for ARM.
#
# x86_64 keeps the historical layout: objects in obj/, programs in bin/,
# libraries next to their sources. Other architectures build side by side:
# obj-<arch>/, bin-<arch>/ and lib/<name>/build-<arch>/.

ARCH ?= x86_64

ifeq ($(filter $(ARCH),x86_64 aarch64),)
    $(error Unsupported ARCH '$(ARCH)' for userspace)
endif

MONTAUK_ROOT := $(abspath $(dir $(lastword $(MAKEFILE_LIST)))/../..)

ifeq ($(ARCH),x86_64)
    ARCH_SUFFIX :=
    ARCH_OUT :=
else
    ARCH_SUFFIX := -$(ARCH)
    ARCH_OUT := build-$(ARCH)/
endif

TOOLCHAIN_PREFIX := $(MONTAUK_ROOT)/toolchain/local/bin/$(ARCH)-montauk-
TOOLCHAIN_MISSING := $(ARCH)-montauk toolchain not found. Run ./toolchain/build-montauk-toolchain.sh $(ARCH) first

# ARCH_FP_FLAGS:   programs that use floating point / SIMD (GUI apps)
# ARCH_NOFP_FLAGS: system programs that must not touch FP/SIMD registers
# ARCH_CFLAGS:     code-model flags the libraries pass explicitly
ifeq ($(ARCH),x86_64)
    ARCH_FP_FLAGS := -msse -msse2
    ARCH_NOFP_FLAGS := -mno-80387 -mno-mmx -mno-sse -mno-sse2
    ARCH_CFLAGS := -m64 -march=x86-64 -mno-red-zone -mcmodel=small
    ARCH_LD_EMULATION := elf_x86_64
else
    ARCH_FP_FLAGS :=
    ARCH_NOFP_FLAGS := -mgeneral-regs-only
    ARCH_CFLAGS := -mcmodel=small
    ARCH_LD_EMULATION := aarch64elf
endif