TASKING VX-toolset for ARM User Guide

TASKING VX-toolset for ARM User GuideHow to overrule the default switch methodYou can overrule the compiler chosen switch method by using a pragma:#pragma linear_switch#pragma jump_switch#pragma binary_switch#pragma smart_switch#pragma tbb_switch#pragma tbh_switch#pragma no_tbh_switchforce jump chain codeforce jump table codeforce binary search table codelet the compiler decide the switch method usedforce use of tbb instruction (uses a table of 8-bit jump offsets)force use of tbh instruction (uses a table of 16-bit jump offsets)same as smart_switch, but do not use tbh instructionUsing a pragma cannot overrule the restrictions as described earlier.The switch pragmas must be placed before the switch statement. Nested switch statements use thesame switch method, unless the nested switch is implemented in a separate function which is precededby a different switch pragma.Example:/* place pragma before function body */#pragma jump_switchvoid test(unsigned char val){ /* function containing the switch */switch (val){/* use jump table */}}1.10. Functions1.10.1. Calling ConventionParameter passingA lot of execution time of an application is spent transferring parameters between functions. The fastestparameter transport is via registers. Therefore, function parameters are first passed via registers. If nomore registers are available for a parameter, the compiler pushes parameters on the stack.Registers available for parameter passing are r0, r1, r2 and r3.22