Imagecraft c compiler and development environment for the atmel avr

ICCV8 for AVR – C Compiler for Atmel AVRCommandsA command can be an AVR instruction, an assembler directive or a macro invocation.The operands field denotes the operands needed for the command. This page doesnot describe the AVR instructions per se, since the assembler uses the standardvendor-defined names; consult the vendor’s documentation for instructiondescriptions.The exceptions are: xcall Applicable to mega devices that support long call or jump instructionsonly. This is translated to either to rcall or call, depending on the location ofthe target label. xjmp Applicable to mega devices that support long call or jump instructionsonly. This is translated to either to rjmp or jmp, depending on the location of thetarget label.ExpressionsAn instruction operand may involve an expression. For example, the direct addressingmode is simply an expression:lds R10,asymbolThe expression asymbol is an example of the simplest expression, which is just asymbol or label name. In general, an expression is described by:expr: term | ( expr ) | unop expr | expr binop exprterm: . | name | #nameThe dot (.) is the current program counter. Parentheses () provide grouping.Operator precedence is given below. Expressions cannot be arbitrarily complex, dueto the limitations of relocation information communicated to the linker. The basic rule isthat for an expression, there can only be only one relocatable symbol. For example,lds R10,foo+baris invalid if both foo and bar are external symbols.OperatorsThe following is the list of the operators and their precedence. Operators with higherprecedence are applied first. Only the addition operator may apply to a relocatablesymbol (such as an external symbol). All other operators must be applied to constantsor symbols resolvable by the assembler (such as a symbol defined in the file).181