HomeMIPS directives
MIPS directives are used to define the structure of the program. They are not instructions that are executed by the CPU, but rather instructions that are used by the assembler to define the structure of the program.
.data
Declares a section for storing initialized data, such as variables.
.text
Declares a section for storing executable instructions. This is where program logic is written.
.kdata
Declares a section for storing kernel-mode initialized data.
.ktext
Declares a section for storing kernel-mode executable instructions.
.word
Allocates one or more 32-bit (4-byte) words in memory.
Example:
values: .word 1, 2, 3, 4
.half
Allocates one or more 16-bit (2-byte) halfwords in memory.
Example:
values: .half 1234, 5678
.byte
Allocates one or more 8-bit (1-byte) values in memory.
Example:
flags: .byte 0, 1, 1, 0
.float
Allocates a single-precision floating-point (32-bit) number in memory.
.double
Allocates a double-precision floating-point (64-bit) number in memory.
.asciiz
Stores a null-terminated string (C-style string).
Example:
message: .asciiz "Hello, world!"
.ascii
Stores a string without a null terminator. Useful when manually handling string length.
.space
Reserves a specified number of bytes in memory without initializing them.
Example:
buffer: .space 100 # Reserves 100 bytes
.align
Aligns the next data to a 2^n-byte boundary.
Example:
.align 2 # Aligns to a 4-byte boundary
.globl
Marks a symbol as global, making it accessible from other files.
Example:
.globl main # Makes 'main' visible to the linker
.extern
Declares a symbol that is defined in another file, specifying its size.
.macro
Defines a macro, which allows writing reusable code blocks.
.end_macro
Ends a macro definition.
.include
Includes an external assembly file.
Example:
.include "myfile.s"
.eqv
Defines a symbolic constant, similar to #define in C.
Example:
.eqv SIZE 10
.set
Configures assembler settings, such as allowing modifications to the $at register.
Example:
.set noat # Allows use of register $at
.bss
Declares an uninitialized data section, typically used for reserving large blocks of memory.
.org
Sets the location counter to a specific address, controlling where subsequent data or code is placed.
.ltorg
Forces the assembler to place literal pools (constants) at the current location.
..frame
Defines a function's stack frame structure, including base register, stack size, and return register.
.ent
Marks the start of a function for debugging or profiling purposes.
.end
Marks the end of an assembly file or function.
.local
Declares a symbol as local, meaning it is only accessible within the current file.