Predefined Macros and Built-in Variables

Predefined Macros

Like other language compilers, the BiSheng Compiler has some predefined macros for developers to write programs.

Predefined Macros	Default Value	Description
__CCE_IS_AICORE__	1	The value is 1 on the device, which can be used to distinguish device code from host code.

Built-in Variables

The following variables are built-in variables of the BiSheng Compiler. The variable names defined by developers in programs cannot be the same as the built-in variable names. Additionally, built-in variables are usually used by the framework and remain imperceptible to developers. To obtain the core ID or number of cores, use the corresponding Ascend C API.

**Table 1** Built-in variable list
Built-in Variable	Description
block_idx	Current core ID, which is a logical value in the core and remains imperceptible to developers. The core ID used during programming can be obtained by calling GetBlockIdx.
block_num	Number of used cores, which is a logical value in the core and remains imperceptible to developers. The number of cores used for programming can be obtained by calling GetBlockNum.

Parent topic: Basic Programming Guide