[En-Nut-Discussion] Strange newlib syscall dependencies / linker problems when using 64bit integers

[Ole Reinhardt]

Hi all,

in one special situation I need to use a 64bit devision on a Cortex M3.
Compiling works fine, but the linker trows the following problems:

arm-eCross-eabi-gcc test.o -mcpu=cortex-m3 -mthumb -mlittle-endian
-D__CORTEX__ -nostartfiles
-L/home/ole/work/Streamit/NutOS_M3N/nut/arch/cm3/ldscripts
-Tlpc1778_flash.ld -Wl,-Map=uart.map,--cref,--gc-sections
-L/home/ole/work/Streamit/nut-build-lpc177x_8x/lib
-Wl,--start-group /home/ole/work/Streamit/nut-build-lpc177x_8x/lib/nutinit.o -lnutcrt -lnutarch -lnutdev -lnutos -lnutdev -lnutarch   -Wl,--end-group -o uart.elf
/opt/arm-eCross-eabi/bin/../lib/gcc/arm-eCross-eabi/4.5.2/../../../../arm-eCross-eabi/lib/thumb/v7m/libc.a(lib_a-abort.o): In function `abort':
/home/ole/work/eCross/newlib-build/arm-eCross-eabi/thumb/v7m/newlib/libc/stdlib/../../../../../../../src/newlib-1.19.0/newlib/libc/stdlib/abort.c:63: undefined reference to `_exit'
/opt/arm-eCross-eabi/bin/../lib/gcc/arm-eCross-eabi/4.5.2/../../../../arm-eCross-eabi/lib/thumb/v7m/libc.a(lib_a-signalr.o): In function `_kill_r':
/home/ole/work/eCross/newlib-build/arm-eCross-eabi/thumb/v7m/newlib/libc/reent/../../../../../../../src/newlib-1.19.0/newlib/libc/reent/signalr.c:61: undefined reference to `_kill'
/opt/arm-eCross-eabi/bin/../lib/gcc/arm-eCross-eabi/4.5.2/../../../../arm-eCross-eabi/lib/thumb/v7m/libc.a(lib_a-signalr.o): In function `_getpid_r':
/home/ole/work/eCross/newlib-build/arm-eCross-eabi/thumb/v7m/newlib/libc/reent/../../../../../../../src/newlib-1.19.0/newlib/libc/reent/signalr.c:96: undefined reference to `_getpid'
/opt/arm-eCross-eabi/bin/../lib/gcc/arm-eCross-eabi/4.5.2/../../../../arm-eCross-eabi/lib/thumb/v7m/libc.a(lib_a-sbrkr.o): In function `_sbrk_r':
/home/ole/work/eCross/newlib-build/arm-eCross-eabi/thumb/v7m/newlib/libc/reent/../../../../../../../src/newlib-1.19.0/newlib/libc/reent/sbrkr.c:60: undefined reference to `_sbrk'
collect2: ld returned 1 exit status


The program itself looks like this:

#include <inttypes.h>
int main()
{
    uint64_t *a,b;
    volatile uint64_t c;
    a = 0xaa000aa00;
    
    b= 0xaa00aa0000550055;
    
    c = b/(*a);

    if (c < 100) return 1;

    while(1);
    return 0;
}

Btw: defining a as pointer is just a trick to trick the optimizer (which
eliminates constant calculations)


Beside the above problem the linker complained about overlapping
sections .data with (implicit?) segments ARM.extab ad ARN.exidx

I fixed this by adding the requested segments (see part of the
lpc17xx_flash.ld linker script below):

   .text :
    {
        . = ALIGN(4);
        _svect = .;
        KEEP(*(.isr_vector))
        _evect = .;
        *(.text .text.* .gnu.linkonce.t.*)
        *(.rodata .rodata* .gnu.linkonce.r.*)
        *(.glue_7t)
        *(.glue_7)
    	*(.gcc_except_table)
	    . = ALIGN(4);
/*        _etext = .;*/
    } > FLASH0

    /* for exception handling/unwind - some Newlib functions (in common
with C++ and STDC++) use this. */

    .ARM.extab : 
    {
        *(.ARM.extab* .gnu.linkonce.armextab.*)
    } >  FLASH0

    __exidx_start = .;
    .ARM.exidx :
    {
        *(.ARM.exidx* .gnu.linkonce.armexidx.*)
    } >  FLASH0
    __exidx_end = .;

    _etext = .;

    .vtable (NOLOAD):
    {
    	. = ALIGN(4);
	    _vtable = .;
	    *(.vtable*)
    	. = ALIGN(4);
	    _evtable = .;
    } > SRAM0


Does anybody has an idea of what is going wrong here?

Best regards,

Ole Reinhardt

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