Because Cortex-M3 does not provide vector catch on SVC, and the vector table contains jump addresses rather than instructions, semihosting cannot be supported using an SVC instruction.

As an alternative, semihosting is implemented using a software breakpoint that is recognized as a semihosting break by the debugger. The specific breakpoint instruction used is set by using the Thumb breakpoint configuration item.

When the semihosting break is executed, the semihosting call is processed in the normal way. After processing, execution continues from the instruction that follows the software breakpoint. The debugger does not stop on the breakpoint.