diff --git a/demos/ARMCM4-STM32F407-DISCOVERY/Makefile b/demos/ARMCM4-STM32F407-DISCOVERY/Makefile
index 84fd1735e..6a60185dc 100644
--- a/demos/ARMCM4-STM32F407-DISCOVERY/Makefile
+++ b/demos/ARMCM4-STM32F407-DISCOVERY/Makefile
@@ -5,7 +5,7 @@
 
 # Compiler options here.
 ifeq ($(USE_OPT),)
-  USE_OPT = -O2 -ggdb -fomit-frame-pointer -falign-functions=16 -mhard-float -mfpu=fpv4-sp-d16
+  USE_OPT = -O2 -ggdb -fomit-frame-pointer -falign-functions=16 -mhard-float -mfpu=fpv4-sp-d16 -fsingle-precision-constant
 endif
 
 # C specific options here (added to USE_OPT).
diff --git a/testhal/STM32F4xx/ADC/Makefile b/testhal/STM32F4xx/ADC/Makefile
index f392d9733..de1ac051f 100644
--- a/testhal/STM32F4xx/ADC/Makefile
+++ b/testhal/STM32F4xx/ADC/Makefile
@@ -5,7 +5,7 @@
 
 # Compiler options here.
 ifeq ($(USE_OPT),)
-  USE_OPT = -O2 -ggdb -fomit-frame-pointer -falign-functions=16 -mhard-float -mfpu=fpv4-sp-d16
+  USE_OPT = -O2 -ggdb -fomit-frame-pointer -falign-functions=16 -mhard-float -mfpu=fpv4-sp-d16 -fsingle-precision-constant
 endif
 
 # C specific options here (added to USE_OPT).
diff --git a/testhal/STM32F4xx/EXT/Makefile b/testhal/STM32F4xx/EXT/Makefile
index f392d9733..de1ac051f 100644
--- a/testhal/STM32F4xx/EXT/Makefile
+++ b/testhal/STM32F4xx/EXT/Makefile
@@ -5,7 +5,7 @@
 
 # Compiler options here.
 ifeq ($(USE_OPT),)
-  USE_OPT = -O2 -ggdb -fomit-frame-pointer -falign-functions=16 -mhard-float -mfpu=fpv4-sp-d16
+  USE_OPT = -O2 -ggdb -fomit-frame-pointer -falign-functions=16 -mhard-float -mfpu=fpv4-sp-d16 -fsingle-precision-constant
 endif
 
 # C specific options here (added to USE_OPT).
diff --git a/testhal/STM32F4xx/GPT/Makefile b/testhal/STM32F4xx/GPT/Makefile
index f392d9733..de1ac051f 100644
--- a/testhal/STM32F4xx/GPT/Makefile
+++ b/testhal/STM32F4xx/GPT/Makefile
@@ -5,7 +5,7 @@
 
 # Compiler options here.
 ifeq ($(USE_OPT),)
-  USE_OPT = -O2 -ggdb -fomit-frame-pointer -falign-functions=16 -mhard-float -mfpu=fpv4-sp-d16
+  USE_OPT = -O2 -ggdb -fomit-frame-pointer -falign-functions=16 -mhard-float -mfpu=fpv4-sp-d16 -fsingle-precision-constant
 endif
 
 # C specific options here (added to USE_OPT).
diff --git a/testhal/STM32F4xx/IRQ_STORM/Makefile b/testhal/STM32F4xx/IRQ_STORM/Makefile
index f392d9733..de1ac051f 100644
--- a/testhal/STM32F4xx/IRQ_STORM/Makefile
+++ b/testhal/STM32F4xx/IRQ_STORM/Makefile
@@ -5,7 +5,7 @@
 
 # Compiler options here.
 ifeq ($(USE_OPT),)
-  USE_OPT = -O2 -ggdb -fomit-frame-pointer -falign-functions=16 -mhard-float -mfpu=fpv4-sp-d16
+  USE_OPT = -O2 -ggdb -fomit-frame-pointer -falign-functions=16 -mhard-float -mfpu=fpv4-sp-d16 -fsingle-precision-constant
 endif
 
 # C specific options here (added to USE_OPT).
diff --git a/testhal/STM32F4xx/IRQ_STORM_FPU/Makefile b/testhal/STM32F4xx/IRQ_STORM_FPU/Makefile
index 0bdb34ed3..aa109bff9 100644
--- a/testhal/STM32F4xx/IRQ_STORM_FPU/Makefile
+++ b/testhal/STM32F4xx/IRQ_STORM_FPU/Makefile
@@ -5,7 +5,7 @@
 
 # Compiler options here.
 ifeq ($(USE_OPT),)
-  USE_OPT = -O2 -ggdb -fomit-frame-pointer -falign-functions=16 -mhard-float -mfpu=fpv4-sp-d16
+  USE_OPT = -O2 -ggdb -fomit-frame-pointer -falign-functions=16 -mhard-float -mfpu=fpv4-sp-d16 -fsingle-precision-constant
 endif
 
 # C specific options here (added to USE_OPT).
diff --git a/testhal/STM32F4xx/IRQ_STORM_FPU/main.c b/testhal/STM32F4xx/IRQ_STORM_FPU/main.c
index a41c931e1..7b751ed3c 100644
--- a/testhal/STM32F4xx/IRQ_STORM_FPU/main.c
+++ b/testhal/STM32F4xx/IRQ_STORM_FPU/main.c
@@ -56,13 +56,13 @@ static msg_t WorkerThread(void *arg) {
   while(1) {
     float f1, f2, f3, f4, f5;
 
-    f1 = ff1(3);
-    f2 = ff1(4);
-    f3 = ff1(5);
+    f1 = ff1(3.0f);
+    f2 = ff1(4.0f);
+    f3 = ff1(5.0f);
     f5 = f1 + f2 + f3;
-    f4 = ff1(6);
+    f4 = ff1(6.0f);
     f5 = ff2(f5, f4, f5, f4);
-    if (f5 != 324)
+    if (f5 != 324.0f)
       chSysHalt();
   }
 }
@@ -78,13 +78,13 @@ static msg_t PeriodicThread(void *arg) {
   while(1) {
     float f1, f2, f3, f4, f5;
 
-    f1 = ff1(4);
-    f2 = ff1(5);
-    f3 = ff1(6);
+    f1 = ff1(4.0f);
+    f2 = ff1(5.0f);
+    f3 = ff1(6.0f);
     f5 = f1 + f2 + f3;
-    f4 = ff1(7);
+    f4 = ff1(7.0f);
     f5 = ff2(f5, f4, f5, f4);
-    if (f5 != 484)
+    if (f5 != 484.0f)
       chSysHalt();
     chThdSleepSeconds(1);
   }
@@ -98,13 +98,13 @@ static void gpt2cb(GPTDriver *gptp) {
 
   (void)gptp;
 
-  f1 = ff1(2);
-  f2 = ff1(3);
-  f3 = ff1(4);
+  f1 = ff1(2.0f);
+  f2 = ff1(3.0f);
+  f3 = ff1(4.0f);
   f5 = f1 + f2 + f3;
-  f4 = ff1(5);
+  f4 = ff1(5.0f);
   f5 = ff2(f5, f4, f5, f4);
-  if (f5 != 196)
+  if (f5 != 196.0f)
     chSysHalt();
 }
 
@@ -116,13 +116,13 @@ static void gpt3cb(GPTDriver *gptp) {
 
   (void)gptp;
 
-  f1 = ff1(1);
-  f2 = ff1(2);
-  f3 = ff1(3);
+  f1 = ff1(1.0f);
+  f2 = ff1(2.0f);
+  f3 = ff1(3.0f);
   f5 = f1 + f2 + f3;
-  f4 = ff1(4);
+  f4 = ff1(4.0f);
   f5 = ff2(f5, f4, f5, f4);
-  if (f5 != 100)
+  if (f5 != 100.0f)
     chSysHalt();
 }
 
diff --git a/testhal/STM32F4xx/PWM-ICU/Makefile b/testhal/STM32F4xx/PWM-ICU/Makefile
index f392d9733..de1ac051f 100644
--- a/testhal/STM32F4xx/PWM-ICU/Makefile
+++ b/testhal/STM32F4xx/PWM-ICU/Makefile
@@ -5,7 +5,7 @@
 
 # Compiler options here.
 ifeq ($(USE_OPT),)
-  USE_OPT = -O2 -ggdb -fomit-frame-pointer -falign-functions=16 -mhard-float -mfpu=fpv4-sp-d16
+  USE_OPT = -O2 -ggdb -fomit-frame-pointer -falign-functions=16 -mhard-float -mfpu=fpv4-sp-d16 -fsingle-precision-constant
 endif
 
 # C specific options here (added to USE_OPT).
diff --git a/testhal/STM32F4xx/RTC/Makefile b/testhal/STM32F4xx/RTC/Makefile
index 7cbe600f6..b41ba0124 100644
--- a/testhal/STM32F4xx/RTC/Makefile
+++ b/testhal/STM32F4xx/RTC/Makefile
@@ -5,7 +5,7 @@
 
 # Compiler options here.
 ifeq ($(USE_OPT),)
-  USE_OPT = -O0 -ggdb -fomit-frame-pointer -falign-functions=16 -mhard-float -mfpu=fpv4-sp-d16
+  USE_OPT = -O0 -ggdb -fomit-frame-pointer -falign-functions=16 -mhard-float -mfpu=fpv4-sp-d16 -fsingle-precision-constant
 endif
 
 # C specific options here (added to USE_OPT).
diff --git a/testhal/STM32F4xx/SPI/Makefile b/testhal/STM32F4xx/SPI/Makefile
index dfc4ac9f0..425e5f6c5 100644
--- a/testhal/STM32F4xx/SPI/Makefile
+++ b/testhal/STM32F4xx/SPI/Makefile
@@ -5,7 +5,7 @@
 
 # Compiler options here.
 ifeq ($(USE_OPT),)
-  USE_OPT = -O2 -ggdb -fomit-frame-pointer -falign-functions=16 -mhard-float -mfpu=fpv4-sp-d16
+  USE_OPT = -O2 -ggdb -fomit-frame-pointer -falign-functions=16 -mhard-float -mfpu=fpv4-sp-d16 -fsingle-precision-constant
 endif
 
 # C specific options here (added to USE_OPT).
diff --git a/testhal/STM32F4xx/UART/Makefile b/testhal/STM32F4xx/UART/Makefile
index f392d9733..de1ac051f 100644
--- a/testhal/STM32F4xx/UART/Makefile
+++ b/testhal/STM32F4xx/UART/Makefile
@@ -5,7 +5,7 @@
 
 # Compiler options here.
 ifeq ($(USE_OPT),)
-  USE_OPT = -O2 -ggdb -fomit-frame-pointer -falign-functions=16 -mhard-float -mfpu=fpv4-sp-d16
+  USE_OPT = -O2 -ggdb -fomit-frame-pointer -falign-functions=16 -mhard-float -mfpu=fpv4-sp-d16 -fsingle-precision-constant
 endif
 
 # C specific options here (added to USE_OPT).