Remember that case is significant in macro names. In fact, the implementation defines the arguments as simple macros. Its manner of definition is the same as for defmacro the only differences. Within the replacement text, the arguments can be substituted by the form: $A. define-compiler-macro name lambda-list declaration documentation form. The name of the macro must begin with a letter and can consist of any combination of letters and numbers. This can be used in more complex situations. #define NAME( a' b' c') - defines a macro with arguments. More flexibility can be obtained by using a macro with arguments, described below. This form is limiting, in that the variable names are fixed. This is similar to, but independent of, the macro system in the score language. This can save typing, and can lead to a coherent structure and consistent style. The orchestra macro system in Csound is a very simple one, and uses the characters # and $ to define and call macros. If the program was already using those registers for keeping important data, then the existing data from these registers should be saved in the stack and restored after the instruction is executed.Macros are textual replacements which are made in the orchestra as it is being read. We have observed that, some instructions like IMUL, IDIV, INT, etc., need some of the information to be stored in some particular registers and even return values in some specific register(s). So, it could be useful to write two macros for saving and restoring data. So, each time you need to display on screen, you need to save these registers on the stack, invoke INT 80H and then restore the original value of the registers from the stack. In the above example of displaying a character string, the registers EAX, EBX, ECX and EDX have been used by the INT 80H function call. For displaying a string of characters, you need the following sequence of instructions − When defined, the macros are expanded to the specified values by the preprocessor before compilation. Except where noted, the macros are defined throughout a translation unit as if they were specified as /D compiler option arguments. When you need to use some sequence of instructions many times in a program, you can put those instructions in a macro and use it instead of writing the instructions all the time.įor example, a very common need for programs is to write a string of characters in the screen. Some macros are defined only for specific build environments or compiler options. The macro is invoked by using the macro name along with the necessary parameters. Where, number_of_params specifies the number parameters, macro_name specifies the name of the macro. The define directive specifies a macro identifier and a replacement list, and terminates with a new-line character. SAS/IML Software and Matrix Computations. The macro begins with the %macro directive and ends with the %endmacro directive. Mathematical Optimization, Discrete-Event Simulation, and OR. In NASM, macros are defined with %macro and %endmacro directives. Writing a macro is another way of ensuring modular programming in assembly language.Ī macro is a sequence of instructions, assigned by a name and could be used anywhere in the program.
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