Imagecraft c compiler and development environment for the atmel avr

ICCV8 for AVR – C Compiler for Atmel AVRFunction PointersTo be fully compatible with the Code Compressor (tm), all indirect function referencesmust be through an extra level of indirection. This is done automatically for you in C ifyou invoke a function by using a function pointer. In other words, function pointersbehave as expected, with the exception of being slightly slower.The following assembly language example illustrates this:; assume _foo is the name of the function.area func_litPL_foo:: .word _foo ; create a function table entry.area textldi R30,PL_foorcall xicallYou may use the library function xicall to call the function indirectly after putting theaddress of the function table entry into the R30/R31 pair. Function table entries are putin a special area called func_lit. See Program Areas.For the M256x targets, the function tables are located in the efunc_lit area andeach entry is 3 bytes long, to allow the function to be located anywhere in the 256Kbytes address space. The function exicall is used instead of xicall, since 3 bytesare used.145