stmhal: Add possibility to build with double-precision floating point.

By default the firmware is built with single-precision floating point.
To build a particular board using double precision instead, put the
following line in the mpconfigboard.mk file:

    FLOAT_IMPL = double

stmhal/Makefile

@@ -48,7 +48,7 @@ INC += -I$(HAL_DIR)/inc
 INC += -I$(USBDEV_DIR)/core/inc -I$(USBDEV_DIR)/class/inc
 #INC += -I$(USBHOST_DIR)
 
-CFLAGS_CORTEX_M = -mthumb -mfpu=fpv4-sp-d16 -mfloat-abi=hard -fsingle-precision-constant -Wdouble-promotion
+CFLAGS_CORTEX_M = -mthumb -mfpu=fpv4-sp-d16 -mfloat-abi=hard
 CFLAGS_MCU_f4 = $(CFLAGS_CORTEX_M) -mtune=cortex-m4 -mcpu=cortex-m4 -DMCU_SERIES_F4
 CFLAGS_MCU_f7 = $(CFLAGS_CORTEX_M) -mtune=cortex-m7 -mcpu=cortex-m7 -DMCU_SERIES_F7
 CFLAGS_MCU_l4 = $(CFLAGS_CORTEX_M) -mtune=cortex-m4 -mcpu=cortex-m4 -DMCU_SERIES_L4
@@ -60,6 +60,13 @@ CFLAGS += $(COPT)
 CFLAGS += -Iboards/$(BOARD)
 CFLAGS += -DSTM32_HAL_H='<stm32$(MCU_SERIES)xx_hal.h>'
 
+ifeq ($(FLOAT_IMPL),double)
+CFLAGS += -DMICROPY_FLOAT_IMPL=MICROPY_FLOAT_IMPL_DOUBLE
+else
+CFLAGS += -DMICROPY_FLOAT_IMPL=MICROPY_FLOAT_IMPL_FLOAT
+CFLAGS += -fsingle-precision-constant -Wdouble-promotion
+endif
+
 LDFLAGS = -nostdlib -L $(LD_DIR) -T $(LD_FILE) -Map=$(@:.elf=.map) --cref
 LIBS = $(shell $(CC) $(CFLAGS) -print-libgcc-file-name)
 
@@ -77,32 +84,6 @@ endif
 
 SRC_LIB = $(addprefix lib/,\
 	libc/string0.c \
-	libm/math.c \
-	libm/thumb_vfp_sqrtf.c \
-	libm/asinfacosf.c \
-	libm/atanf.c \
-	libm/atan2f.c \
-	libm/fmodf.c \
-	libm/nearbyintf.c \
-	libm/log1pf.c \
-	libm/acoshf.c \
-	libm/asinhf.c \
-	libm/atanhf.c \
-	libm/kf_rem_pio2.c \
-	libm/kf_sin.c \
-	libm/kf_cos.c \
-	libm/kf_tan.c \
-	libm/ef_rem_pio2.c \
-	libm/erf_lgamma.c \
-	libm/sf_sin.c \
-	libm/sf_cos.c \
-	libm/sf_tan.c \
-	libm/sf_frexp.c \
-	libm/sf_modf.c \
-	libm/sf_ldexp.c \
-	libm/sf_erf.c \
-	libm/wf_lgamma.c \
-	libm/wf_tgamma.c \
 	oofatfs/ff.c \
 	oofatfs/option/unicode.c \
 	mp-readline/readline.c \
@@ -113,6 +94,81 @@ SRC_LIB = $(addprefix lib/,\
 	utils/sys_stdio_mphal.c \
 	)
 
+ifeq ($(FLOAT_IMPL),double)
+SRC_LIBM = $(addprefix lib/libm_dbl/,\
+	__cos.c \
+	__expo2.c \
+	__fpclassify.c \
+	__rem_pio2.c \
+	__rem_pio2_large.c \
+	__signbit.c \
+	__sin.c \
+	__tan.c \
+	acos.c \
+	acosh.c \
+	asin.c \
+	asinh.c \
+	atan.c \
+	atan2.c \
+	atanh.c \
+	ceil.c \
+	cos.c \
+	cosh.c \
+	erf.c \
+	exp.c \
+	expm1.c \
+	floor.c \
+	fmod.c \
+	frexp.c \
+	ldexp.c \
+	lgamma.c \
+	log.c \
+	log10.c \
+	log1p.c \
+	modf.c \
+	nearbyint.c \
+	pow.c \
+	rint.c \
+	scalbn.c \
+	sin.c \
+	sinh.c \
+	sqrt.c \
+	tan.c \
+	tanh.c \
+	tgamma.c \
+	trunc.c \
+	)
+else
+SRC_LIBM = $(addprefix lib/libm/,\
+	math.c \
+	thumb_vfp_sqrtf.c \
+	acoshf.c \
+	asinfacosf.c \
+	asinhf.c \
+	atan2f.c \
+	atanf.c \
+	atanhf.c \
+	ef_rem_pio2.c \
+	erf_lgamma.c \
+	fmodf.c \
+	kf_cos.c \
+	kf_rem_pio2.c \
+	kf_sin.c \
+	kf_tan.c \
+	log1pf.c \
+	nearbyintf.c \
+	sf_cos.c \
+	sf_erf.c \
+	sf_frexp.c \
+	sf_ldexp.c \
+	sf_modf.c \
+	sf_sin.c \
+	sf_tan.c \
+	wf_lgamma.c \
+	wf_tgamma.c \
+	)
+endif
+
 EXTMOD_SRC_C = $(addprefix extmod/,\
 	modonewire.c \
         )
@@ -258,6 +314,7 @@ endif
 OBJ =
 OBJ += $(PY_O)
 OBJ += $(addprefix $(BUILD)/, $(SRC_LIB:.c=.o))
+OBJ += $(addprefix $(BUILD)/, $(SRC_LIBM:.c=.o))
 OBJ += $(addprefix $(BUILD)/, $(EXTMOD_SRC_C:.c=.o))
 OBJ += $(addprefix $(BUILD)/, $(DRIVERS_SRC_C:.c=.o))
 OBJ += $(addprefix $(BUILD)/, $(SRC_C:.c=.o))

stmhal/mpconfigport.h

@@ -65,7 +65,9 @@
 #define MICROPY_REPL_AUTO_INDENT    (1)
 #define MICROPY_LONGINT_IMPL        (MICROPY_LONGINT_IMPL_MPZ)
 #define MICROPY_ENABLE_SOURCE_LINE  (1)
+#ifndef MICROPY_FLOAT_IMPL // can be configured by each board via mpconfigboard.mk
 #define MICROPY_FLOAT_IMPL          (MICROPY_FLOAT_IMPL_FLOAT)
+#endif
 #define MICROPY_STREAMS_NON_BLOCK   (1)
 #define MICROPY_MODULE_WEAK_LINKS   (1)
 #define MICROPY_CAN_OVERRIDE_BUILTINS (1)