Projectkk2glider/hardware floating point (#4477)

* Turn on compiler hardware floating point support for F4 targets

* Fixes, works on Horus

* Comment updated

radio/src/CMakeLists.txt

@@ -434,6 +434,7 @@ if(NOT MSVC)
     set(CMAKE_ASM_COMPILE_OBJECT "<CMAKE_ASM_COMPILER> -o <OBJECT> <SOURCE>")
 
     set(COMMON_FLAGS "-mcpu=${MCU} -mthumb -fomit-frame-pointer -fverbose-asm -Wa,-ahlms=firmware.lst -O${OPT} -gdwarf-2 -DHSE_VALUE=${HSE_VALUE} -fno-exceptions -fdata-sections -ffunction-sections ${WARNING_FLAGS}")
+    set(COMMON_FLAGS "${COMMON_FLAGS} ${FPU_FLAGS}")
 
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${COMMON_FLAGS} -Wimplicit")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${COMMON_FLAGS}")

radio/src/targets/common/arm/stm32/f2/CMakeLists.txt

@@ -1,5 +1,6 @@
 set(CPU_FAMILY STM32)
 set(MCU cortex-m3)
+set(FPU_FLAGS "")
 set(STM32LIB_DIR ${THIRDPARTY_DIR}/STM32F2xx_StdPeriph_Lib_V1.1.0/Libraries)
 include_directories(${STM32LIB_DIR}/STM32F2xx_StdPeriph_Driver/inc)
 include_directories(${STM32LIB_DIR}/CMSIS/Device/ST/STM32F2xx/Include)

radio/src/targets/common/arm/stm32/f4/CMakeLists.txt

@@ -1,5 +1,6 @@
 set(CPU_FAMILY STM32)
 set(MCU cortex-m4)
+set(FPU_FLAGS "-mfloat-abi=hard -mfpu=fpv4-sp-d16")
 set(STM32LIB_DIR ${THIRDPARTY_DIR}/STM32F4xx_DSP_StdPeriph_Lib_V1.4.0/Libraries)
 include_directories(${STM32LIB_DIR}/STM32F4xx_StdPeriph_Driver/inc)
 include_directories(${STM32LIB_DIR}/CMSIS/Device/ST/STM32F4xx/Include)

radio/src/thirdparty/CoOS/OsConfig.h

@@ -43,9 +43,14 @@
 
 
 /*!< 
-Defines chip type,cortex-m3(1),cortex-m0(2)      
+Defines chip type,cortex-m3(1),cortex-m0(2), cortex-m4 without FPU(1), cortex-m4 with FPU(3)
 */
-#define CFG_CHIP_TYPE           (1)
+
+#if defined(STM32F4)
+  #define CFG_CHIP_TYPE           (3)   // this add support for hardware floating point unit (saves registers on stack)
+#else
+  #define CFG_CHIP_TYPE           (1)
+#endif
 
 /*!< 
 Defines the lowest priority that be assigned.