I am trying to figure out how should I enable soft floating point support for arm-none-eabi-gcc
编译器。 The version of arm-none-eabi-gcc
是 gcc version 6.3.1 20170620 (15:6.3.1+svn253039-1build1)
。
I have a Makefile with following compiler and linker options:
CFLAGS = -W -Wall -O0 --std=gnu99 -fgnu89-inline -mcpu=cortex-m3 -mthumb -msoft-float
CFLAGS += -ffunction-sections -fdata-sections -mfloat-abi=soft -u _printf_float -u _scanf_float
LDFLAGS = -nostartfiles -specs=rdimon.specs -specs=nano.specs -lc -lrdimon -u _printf_float -u _scanf_float
But even after compiling with these options I am not able to use float
或double
, for e.g. the code doesn't execute after, if I try to typecast double to long e.g.
long var_tempNumber_u32;
double var_floatNumber_f32;
var_tempNumber_u32 = (long)var_floatNumber_f32;
I am using a custom linker script and as per this NXP Community Link I have added GROUP(libgcc.a libc.a libm.a)
之前SECTIONS
line in linker script.
I am working on LPC1768 micro-controller.
Update:
After some findings I found out that Cortex-M3 is going into Hard Fault handler, so I installed a custom hard-fault handler to get the stack trace and I found out that my firmware is crashing after returning from __aeabi_d2uiz
功能。
Contents of ARM registers at the time of Hard Fault:
r0: 0x81
r1: 0x43C0
r2: 0xC000
r3: 0x1
r12: 0x0000000000
LR: 0xBB1B
PC: 0x884A
Excerpt from the disassembly:
0000baf0 <UART_TxFloatNumber>:
baf0: b590 push {r4, r7, lr}
baf2: b085 sub sp, #20
baf4: af00 add r7, sp, #0
baf6: e9c7 0100 strd r0, r1, [r7]
bafa: 205a movs r0, #90 ; 0x5a
bafc: f7fe fcc8 bl a490 <xMBPortSerialPutByte>
bb00: 2058 movs r0, #88 ; 0x58
bb02: f7fe fcc5 bl a490 <xMBPortSerialPutByte>
bb06: 200d movs r0, #13
bb08: f7fe fcc2 bl a490 <xMBPortSerialPutByte>
bb0c: 200a movs r0, #10
bb0e: f7fe fcbf bl a490 <xMBPortSerialPutByte>
bb12: e9d7 0100 ldrd r0, r1, [r7]
bb16: f7fc fce5 bl 84e4 <__aeabi_d2uiz>
bb1a: 4603 mov r3, r0
bb1c: 60fb str r3, [r7, #12]
bb1e: 21ff movs r1, #255 ; 0xff
bb20: 68f8 ldr r0, [r7, #12]
bb22: f7ff ff5d bl b9e0 <UART_TxDecimalNumber>
bb26: 202e movs r0, #46 ; 0x2e
bb28: f7ff febc bl b8a4 <uart3_tx_byte>
bb2c: 68f8 ldr r0, [r7, #12]
bb2e: f7fc f91f bl 7d70 <__aeabi_ui2d>
bb32: 4603 mov r3, r0
bb34: 460c mov r4, r1
bb36: 461a mov r2, r3
bb38: 4623 mov r3, r4
bb3a: e9d7 0100 ldrd r0, r1, [r7]
bb3e: f7fb ff8d bl 7a5c <__aeabi_dsub>
bb42: 4603 mov r3, r0
bb44: 460c mov r4, r1
bb46: e9c7 3400 strd r3, r4, [r7]
bb4a: a30b add r3, pc, #44 ; (adr r3, bb78 <UART_TxFloatNumber+0x88>)
bb4c: e9d3 2300 ldrd r2, r3, [r3]
bb50: e9d7 0100 ldrd r0, r1, [r7]
bb54: f7fc f98c bl 7e70 <__aeabi_dmul>
bb58: 4603 mov r3, r0
bb5a: 460c mov r4, r1
bb5c: 4618 mov r0, r3
bb5e: 4621 mov r1, r4
bb60: f7fc fcc0 bl 84e4 <__aeabi_d2uiz>
bb64: 4603 mov r3, r0
bb66: 60fb str r3, [r7, #12]
bb68: 21ff movs r1, #255 ; 0xff
bb6a: 68f8 ldr r0, [r7, #12]
bb6c: f7ff ff38 bl b9e0 <UART_TxDecimalNumber>
bb70: bf00 nop
bb72: 3714 adds r7, #20
bb74: 46bd mov sp, r7
bb76: bd90 pop {r4, r7, pc}
bb78: 00000000 andeq r0, r0, r0
bb7c: 412e8480 smlawbmi lr, r0, r4, r8
The address in Link Register is pointing to the instruction inside the above function which is after __aeabi_d2uiz
library function call.
I am not that expert in assembly so I am not able to find the root cause of it.
I also tried increasing the .stackarea
i.e. stack size of my application firmware without any luck.
Please anyone, let me know how to find a possible resolution of this issue.
最佳答案
经过调试和在互联网上搜索了一下,我找到了这个问题的根本原因。
问题出在链接描述文件中,没有为 ARM 堆栈展开定义任何部分。
因此,我将以下行添加到链接器脚本文件中:
.ARM.extab :
{
*(.ARM.extab* .gnu.linkonce.armextab.*)
} > IROM
/*
* Arm stack unwinding.
* If removed may cause random crashes.
*/
.ARM.exidx :
{
__exidx_start = .;
*(.ARM.exidx* .gnu.linkonce.armexidx.*)
__exidx_end = .;
} > IROM
问题已解决。
递归函数需要堆栈展开,因为浮点到整数转换的 GCC 库函数调用是递归的,所以需要堆栈展开,而这是以前不存在的。
关于gcc - 启用GCC-Arm-None-EABI中的浮点仿真,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/54534700/