int __semihost(int val, const void *ptr)

where:

See Semihosting for more information about these parameters.

See Semihosting for more information on the results of semihosting calls.

Use this intrinsic from C or C++ to generate the appropriate semihosting call for your target and instruction set:

ARM processors prior to ARMv7 use SVC instructions to make semihosting calls. However, if you are compiling for a Cortex M-profile processor, semihosting is implemented using the BKPT instruction.

char buffer[100];
...
void foo(void)
{
    __semihost(0x01, (const void *)buf); // equivalent in thumb state to 
                                         // int __svc(0xAB) my_svc(int, int *);
                                         // result = my_svc(0x1, &buffer);
}

Compiling this code with the option --thumb generates:

||foo|| PROC
    ...
    LDR      r1,|L1.12|
    MOVS     r0,#1
    SVC      #0xab
    ...
|L1.12|
    ...
buffer
    %        400