blackfin gcc-toolchain linking error undefined reference to `Ret_Add'

Question

Following discution:

https://blackfin.uclinux.org/gf/project/uclinux-dist/forum/?_forum_action=ForumMessageBrowse&thread_id=46813&action=ForumBrowse&forum_id=39

I'm converting the FFT algo for VDSP compiler to bare metal app to run on core B and have uclinux running on core A. I've a linking error I do not understand where it come from:

Invoking: '/opt/uClinux/bfin-elf/bin/../bfin-elf/bin/ld.real' '-v' '-o' 'test_ad1836_driver' '-T' 'coreb_test_ad1836_driver.lds' '--just-symbol' '../../icc_core/icc' 'queue.o' 'ezkit_561.o' 'heap_2.o' 'port.o' 'tasks.o' 'test_ad1836_driver.o' 'list.o' 'croutine.o' 'user_isr.o' 'bfin_isr.o' 'app_c.o' 'context_sl_asm.o' 'cycle_count.o' 'CFFT_Rad4_NS_NBRev.o' '-Ttext' '0x3c00000' '-L' '/opt/uClinux/bfin-elf/bfin-elf/lib' '-L' '/opt/uClinux/bfin-elf/bfin-elf/lib' '-lc' GNU ld version 2.17 cycle_count.o: In function Compute_Cycle_Count': /home/william/Development_new/Music_Recognition/code/uCLinux/uclinux-dist/user/blkfin-apps/icc_utils/example/DSP_imp/CFFT_Rad4_NS_NBRev/corea/cycle_count.asm:22: undefined reference toRet_Add' /home/william/Development_new/Music_Recognition/code/uCLinux/uclinux-dist/user/blkfin-apps/icc_utils/example/DSP_imp/CFFT_Rad4_NS_NBRev/corea/cycle_count.asm:23: undefined reference to Ret_Add' /home/william/Development_new/Music_Recognition/code/uCLinux/uclinux-dist/user/blkfin-apps/icc_utils/example/DSP_imp/CFFT_Rad4_NS_NBRev/corea/cycle_count.asm:27: undefined reference toSave_R7' /home/william/Development_new/Music_Recognition/code/uCLinux/uclinux-dist/user/blkfin-apps/icc_utils/example/DSP_imp/CFFT_Rad4_NS_NBRev/corea/cycle_count.asm:28: undefined reference to Save_R7' /home/william/Development_new/Music_Recognition/code/uCLinux/uclinux-dist/user/blkfin-apps/icc_utils/example/DSP_imp/CFFT_Rad4_NS_NBRev/corea/cycle_count.asm:44: undefined reference toSave_R7' /home/william/Development_new/Music_Recognition/code/uCLinux/uclinux-dist/user/blkfin-apps/icc_utils/example/DSP_imp/CFFT_Rad4_NS_NBRev/corea/cycle_count.asm:45: undefined reference to Save_R7' /home/william/Development_new/Music_Recognition/code/uCLinux/uclinux-dist/user/blkfin-apps/icc_utils/example/DSP_imp/CFFT_Rad4_NS_NBRev/corea/cycle_count.asm:48: undefined reference toRet_Add' /home/william/Development_new/Music_Recognition/code/uCLinux/uclinux-dist/user/blkfin-apps/icc_utils/example/DSP_imp/CFFT_Rad4_NS_NBRev/corea/cycle_count.asm:49: undefined reference to `Ret_Add'

the code looks like:

.section l1.data;
.align 4;
.var _Ret_Add =0;
.var _Save_R7 =0;

.section l1.text;
.global _Compute_Cycle_Count;
.align 8;
_Compute_Cycle_Count: P0.L = _Ret_Add;
P0.H = _Ret_Add;
R3 = RETS;
[P0] = R3;

    P0.L = _Save_R7;                                                       
    P0.H = _Save_R7;                                                       
    [P0] = R7; 

........

Thanks

William

Answer 1

You have no declaration of _Ret_Add and _Save_R7 in your code to be understood by GNU assembler. You should port it from VDSP asm to GNU asm:

_Ret_Add: .int 0;

or maybe if you prefer keep it backwards compatible:

.if defined (__GNUC__)
_Ret_Add:
.int 0;
.else
.var _Ret_Add =0;
.endif

Take a look at this.