From 87099b57314f37e19f6551b0d575b620e1d29323 Mon Sep 17 00:00:00 2001
From: Alessandro Gatti <a.gatti@frob.it>
Date: Thu, 24 Jul 2025 15:28:48 +0200
Subject: [PATCH] qemu/Makefile: Allow overriding floating point mode by
 boards.

This commit lets board use a different floating point mode rather than
the usual soft-float that was the original default for all QEMU-based
boards.

The configuration options are the same available in the "stm32" port.
Boards can set "MICROPY_FLOAT_IMPL" to either "float", "double", or
"none" to indicate which floating point mode they want, and optionally
"SUPPORTS_HARDWARE_FP_SINGLE" or "SUPPORTS_HARDWARE_FP_DOUBLE" can be
set to 1 to further indicate the hardware capabilities of the hardware
floating point unit, if present.

Signed-off-by: Alessandro Gatti <a.gatti@frob.it>
---
 ports/qemu/Makefile       | 37 +++++++++++++++++++++++++++++++++----
 ports/qemu/mpconfigport.h |  1 -
 2 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/ports/qemu/Makefile b/ports/qemu/Makefile
index fc1e557974..7784a266c3 100644
--- a/ports/qemu/Makefile
+++ b/ports/qemu/Makefile
@@ -36,6 +36,8 @@ MICROPY_HEAP_SIZE ?= 143360
 FROZEN_MANIFEST ?= "require('unittest'); freeze('test-frzmpy', ('frozen_asm_rv32.py', 'frozen_const.py', 'frozen_viper.py', 'native_frozen_align.py'))"
 endif
 
+MICROPY_FLOAT_IMPL ?= float
+
 # include py core make definitions
 include $(TOP)/py/py.mk
 include $(TOP)/extmod/extmod.mk
@@ -44,6 +46,20 @@ GIT_SUBMODULES += lib/berkeley-db-1.xx
 
 CFLAGS += -DMICROPY_HEAP_SIZE=$(MICROPY_HEAP_SIZE)
 
+ifeq ($(MICROPY_FLOAT_IMPL),double)
+CFLAGS += -DMICROPY_FLOAT_IMPL=MICROPY_FLOAT_IMPL_DOUBLE
+else ifeq ($(MICROPY_FLOAT_IMPL),float)
+CFLAGS += -DMICROPY_FLOAT_IMPL=MICROPY_FLOAT_IMPL_FLOAT -fsingle-precision-constant
+else
+CFLAGS += -DMICROPY_FLOAT_IMPL=MICROPY_FLOAT_IMPL_NONE
+endif
+
+ifeq ($(SUPPORTS_HARDWARE_FP_SINGLE),1)
+CFLAGS += -DMICROPY_HW_FPU=1
+else ifeq ($(SUPPORTS_HARDWARE_FP_DOUBLE),1)
+CFLAGS += -DMICROPY_HW_FPU=1
+endif
+
 ################################################################################
 # ARM specific settings
 
@@ -156,16 +172,29 @@ SRC_C += \
 	shared/runtime/stdout_helpers.c \
 	shared/runtime/sys_stdio_mphal.c \
 
-LIB_SRC_C += $(SRC_LIB_LIBM_C)
-LIB_SRC_C += $(SRC_LIB_LIBM_SQRT_SW_C)
+ifeq ($(MICROPY_FLOAT_IMPL),double)
+LIBM_SRC_C += $(SRC_LIB_LIBM_DBL_C)
+ifeq ($(SUPPORTS_HARDWARE_FP_DOUBLE),1)
+LIBM_SRC_C += $(SRC_LIB_LIBM_DBL_SQRT_HW_C)
+else
+LIBM_SRC_C += $(SRC_LIB_LIBM_DBL_SQRT_SW_C)
+endif
+else
+LIBM_SRC_C += $(SRC_LIB_LIBM_C)
+ifeq ($(SUPPORTS_HARDWARE_FP_SINGLE),1)
+LIBM_SRC_C += $(SRC_LIB_LIBM_SQRT_HW_C)
+else
+LIBM_SRC_C += $(SRC_LIB_LIBM_SQRT_SW_C)
+endif
+endif
 
 OBJ += $(PY_O)
 OBJ += $(addprefix $(BUILD)/, $(SRC_C:.c=.o))
 OBJ += $(addprefix $(BUILD)/, $(SRC_BOARD_O))
-OBJ += $(addprefix $(BUILD)/, $(LIB_SRC_C:.c=.o))
+OBJ += $(addprefix $(BUILD)/, $(LIBM_SRC_C:.c=.o))
 
 # List of sources for qstr extraction
-SRC_QSTR += $(SRC_C) $(LIB_SRC_C)
+SRC_QSTR += $(SRC_C) $(LIBM_SRC_C)
 
 ################################################################################
 # Main targets
diff --git a/ports/qemu/mpconfigport.h b/ports/qemu/mpconfigport.h
index 9c879f55df..6c6dd68535 100644
--- a/ports/qemu/mpconfigport.h
+++ b/ports/qemu/mpconfigport.h
@@ -51,7 +51,6 @@
 #define MICROPY_ENABLE_GC           (1)
 #define MICROPY_ENABLE_EMERGENCY_EXCEPTION_BUF (1)
 #define MICROPY_LONGINT_IMPL        (MICROPY_LONGINT_IMPL_MPZ)
-#define MICROPY_FLOAT_IMPL          (MICROPY_FLOAT_IMPL_FLOAT)
 #define MICROPY_WARNINGS            (1)
 #define MICROPY_PY_SYS_PLATFORM     "qemu"
 #define MICROPY_PY_SYS_STDIO_BUFFER (0)