arch/x86/soc/ia32/Makefile - third_party/github/zephyrproject-rtos/zephyr - Git at Google

 ifeq ($(CONFIG_X86_IAMCU),y)
 LD_TOOLCHAIN ?= -D__GCC_LINKER_CMD__ -D__IAMCU
 OUTPUT_FORMAT = elf32-iamcu
 OUTPUT_ARCH = iamcu:intel
 soc-cflags = $(call cc-option,-msoft-float)
 endif

 soc-cflags += $(call cc-option,-march=pentium)
	ifeq ($(CONFIG_X86_IAMCU),y)
	LD_TOOLCHAIN ?= -D__GCC_LINKER_CMD__ -D__IAMCU
	OUTPUT_FORMAT = elf32-iamcu
	OUTPUT_ARCH = iamcu:intel
	soc-cflags = $(call cc-option,-msoft-float)
	endif

	soc-cflags += $(call cc-option,-march=pentium)