Michael Shimniok

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11 years ago.

rtos - offline compile not working and assembler makefile problem

Starting with a basic example rtos program for flashing LEDs, it works fine (of course) with online compile. Then I export for CodeSourcery.

In the makefile AS is defined as arm-none-eabi-as but the makefile uses CFLAGS including numerous gcc options unrecognized by as. When I change the Makefile to instead use arm-none-eabi-gcc for AS it compiles cleanly.

However, the code doesn't work.

I'm happy to help troubleshoot / fix but will need a little help. Perhaps it is time for me to start playing with the debugger I've read about...

I'm compiling on Linux with CodeSourcery gcc 4.7.2 (Sourcery CodeBench Lite) on Linux Mint 14, 3.5.0-17-generic #28-Ubuntu.

Thanks in advance,

Michael

PS: Here's the code I'm using:

three threads, flash leds, works fine with online compile

#include "mbed.h"
#include "rtos.h"

Serial pc(USBTX, USBRX);
DigitalOut led1(LED1);
DigitalOut led2(LED2);
DigitalOut led3(LED3);

void led1_thread(void const *args) {
    while (true) {
        pc.printf("Hello 1\n");
        led1 = !led1;
        Thread::wait(700);
    }
}

void led2_thread(void const *args) {
    while (true) {
        fprintf(stdout, "Hello 2\n");
        led2 = !led2;
        Thread::wait(1000);
    }
}
 
int main() {
    pc.baud(115200);

    Thread t1(led1_thread);
    Thread t2(led2_thread);
    
    while (true) {
        fprintf(stdout, "Hello 3\n");
        led3 = !led3;
        Thread::wait(500);
    }
}

I set up a custom hard fault handler. Here's what it reports:

[Hard fault]
R0 = 0x0000
R1 = 0x0000
R2 = 0x0000
R3 = 0x100006d0
R12 = 0x0059
LR [R14] = 0x066d  subroutine call return address.
PC [R15] = 0x066c  program counter
PSR = 0x61000000 ZC Thread mode  thumb
HFSR = 0x40000000 FORCED 
CFSR = 0x00000400
UFSR = 0x0000 
BFSR = 0x00 
MMFSR = 0x00 
BFAR = invalid
MMFAR = invalid
DFSR = 0x00000008
AFSR = 0x00000000
SCB_SHCSR = 0x00000000

gdb listing, disassembly:

(gdb) list *0x066d
0x66d is in rt_dispatch (mbed-rtos/rtx/rt_Task.c:130).
125	  else {
126	    /* Check which task continues */
127	    if (next_TCB->prio > os_tsk.run->prio) {
128	      /* preempt running task */
129	      rt_put_rdy_first (os_tsk.run);
130	      os_tsk.run->state = READY;
131	      rt_switch_req (next_TCB);
132	    }
133	    else {
134	      /* put next task into ready list, no task switch takes place */

and

(gdb) disass 0x066d
Dump of assembler code for function rt_dispatch:
   0x0000064c <+0>:	push	{r4, r5, r6, lr}
   0x0000064e <+2>:	mov	r4, r0
   0x00000650 <+4>:	cbnz	r0, 0x65a <rt_dispatch+14>
   0x00000652 <+6>:	ldmia.w	sp!, {r4, r5, r6, lr}
   0x00000656 <+10>:	b.w	0x5cc <rt_dispatch>
   0x0000065a <+14>:	ldr	r5, [pc, #44]	; (0x688 <rt_dispatch+60>)
   0x0000065c <+16>:	ldrb	r2, [r4, #2]
   0x0000065e <+18>:	ldr	r0, [r5, #0]
   0x00000660 <+20>:	movs	r6, #1
   0x00000662 <+22>:	ldrb	r3, [r0, #2]
   0x00000664 <+24>:	cmp	r2, r3
   0x00000666 <+26>:	bls.n	0x678 <rt_dispatch+44>
   0x00000668 <+28>:	bl	0x89c <rt_put_rdy_first>
   0x0000066c <+32>:	ldr	r3, [r5, #0]
   0x0000066e <+34>:	strb	r6, [r3, #1]
   0x00000670 <+36>:	movs	r3, #2
   0x00000672 <+38>:	str	r4, [r5, #4]
   0x00000674 <+40>:	strb	r3, [r4, #1]
   0x00000676 <+42>:	pop	{r4, r5, r6, pc}
   0x00000678 <+44>:	ldr	r0, [pc, #16]	; (0x68c <rt_dispatch+64>)
   0x0000067a <+46>:	mov	r1, r4
   0x0000067c <+48>:	strb	r6, [r4, #1]
   0x0000067e <+50>:	ldmia.w	sp!, {r4, r5, r6, lr}
   0x00000682 <+54>:	b.w	0x848 <rt_put_prio>
   0x00000686 <+58>:	nop
   0x00000688 <+60>:	lsls	r4, r5, #26
   0x0000068a <+62>:	asrs	r0, r0, #32
   0x0000068c <+64>:	lsls	r0, r2, #27
   0x0000068e <+66>:	asrs	r0, r0, #32
End of assembler dump.

So I gather there is some issue at ...

<<code>> 0x0000066c <+32>: ldr r3, [r5, #0]<</code>>

What's your target? Can you include those errors?

posted by Martin Kojtal 22 Dec 2013

Target is mbed LPC1768.

Here's the error:

arm-none-eabi-as  -c -Os -fno-common -fmessage-length=0 -Wall -fno-exceptions -mcpu=cortex-m3 -mthumb -ffunction-sections -fdata-sections  -DTARGET_LPC1768 -DTARGET_M3 -DTARGET_NXP -DTARGET_LPC176X -DTOOLCHAIN_GCC_CS -DTOOLCHAIN_GCC -D__CORTEX_M3 -DARM_MATH_CM3  -o mbed-rtos/rtx/TARGET_M3/TOOLCHAIN_GCC/SVC_Table.o mbed-rtos/rtx/TARGET_M3/TOOLCHAIN_GCC/SVC_Table.s
arm-none-eabi-as: unrecognized option '-Os'
make: *** [mbed-rtos/rtx/TARGET_M3/TOOLCHAIN_GCC/SVC_Table.o] Error 1

AS is defined to use arm-none-eabi-as

AS = $(GCC_BIN)arm-none-eabi-as

And as is set up to use CC_FLAGS, but my version doesn't recognize CFLAGS like -Os and -ffunction-sections and whatnot.

.s.o:
	$(AS)  $(CC_FLAGS) $(CC_SYMBOLS) -o $@ $<
posted by Michael Shimniok 22 Dec 2013

Updated with some additional debugging information collected so far.

posted by Michael Shimniok 05 Jan 2014

1 Answer

Michael Shimniok
poster
11 years ago.

oops. I should've commented on the comment/answer above. Nevermind...