From 75154ebdfbbfe7a04d21d910254058a757d2eef6 Mon Sep 17 00:00:00 2001
From: David Phillips <david@yeah.nah.nz>
Date: Sun, 20 Dec 2020 22:22:17 +1300
Subject: Use float-enabled printf implementation

I hadn't realised there is a float-enabled printf implementation in AVR libc,
so let's use that instead of our own hack.
---
 Makefile | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

(limited to 'Makefile')

diff --git a/Makefile b/Makefile
index 3c15800..bb26ce1 100644
--- a/Makefile
+++ b/Makefile
@@ -5,8 +5,13 @@ QEMU_AVR ?= qemu-system-avr
 
 MCU ?= atmega32u4
 SIM_MCU ?= atmega2560
-CFLAGS += -Wall -Wextra -DF_CPU=16000000UL -mmcu=$(MCU) -O3
-SIM_CFLAGS += -Wall -Wextra -DF_CPU=16000000UL -mmcu=$(SIM_MCU) -g3 -gdwarf-2 -DWDT_DISABLE
+COMMON_CFLAGS += -Wall -Wextra -DF_CPU=16000000UL
+CFLAGS += $(COMMON_CFLAGS) -mmcu=$(MCU) -O3
+SIM_CFLAGS += $(COMMON_CFLAGS) -mmcu=$(SIM_MCU) -g3 -gdwarf-2 -DWDT_DISABLE
+
+COMMON_LDFLAGS += -Wl,-u,vfprintf -lprintf_flt
+LDFLAGS += $(COMMON_LDFLAGS) -mmcu=$(MCU)
+SIM_LDFLAGS += $(COMMON_LDFLAGS) -mmcu=$(SIM_MCU)
 
 $(shell mkdir -p build/{real,sim})
 
@@ -26,14 +31,14 @@ build/altimeter.elf: \
 	build/real/display_sim.o \
 	build/real/altimeter.o \
 	build/real/util.o
-	$(CC) -o $@ $^ $(CFLAGS)
+	$(CC) -o $@ $^ $(LDFLAGS)
 
 build/altimeter_sim.elf: \
 	build/sim/barometer_sim.o \
 	build/sim/display_sim.o \
 	build/sim/altimeter.o \
 	build/sim/util.o
-	$(CC) -o $@ $^ $(SIM_CFLAGS)
+	$(CC) -o $@ $^ $(SIM_LDFLAGS)
 
 include config.mk
 
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