MIPS directives

Declares a section for storing initialized data, such as variables.

Declares a section for storing executable instructions. This is where program logic is written.

Declares a section for storing kernel-mode initialized data.

Declares a section for storing kernel-mode executable instructions.

Allocates one or more 32-bit (4-byte) words in memory.

Example:

values: .word 1, 2, 3, 41

Allocates one or more 16-bit (2-byte) halfwords in memory.

Example:

values: .half 1234, 56781

Allocates one or more 8-bit (1-byte) values in memory.

Example:

flags: .byte 0, 1, 1, 01

Allocates a single-precision floating-point (32-bit) number in memory.

Allocates a double-precision floating-point (64-bit) number in memory.

Stores a null-terminated string (C-style string).

Example:

message: .asciiz "Hello, world!"1

Stores a string without a null terminator. Useful when manually handling string length.

Reserves a specified number of bytes in memory without initializing them.

Example:

buffer: .space 100   # Reserves 100 bytes1

Aligns the next data address to a boundary of 2^n bytes: .align 2 moves it to a 4-byte boundary, and .align 3 to an 8-byte boundary. The operand is an exponent, not a byte count.

Example:

.align 2   # Aligns to a 4-byte boundary1

Marks a symbol as global so other source files or a linker can refer to it. For example, .globl main gives the symbol main external visibility.

Example:

.globl main1

Declares an external data symbol and its size in bytes, so the assembler can reserve its address for references to that symbol.

Defines a macro, which allows writing reusable code blocks.

Ends a macro definition.

Includes an external assembly file.

Example:

.include "myfile.s"1

Defines a symbolic constant, similar to #define in C.

Example:

.eqv SIZE 101

Configures assembler settings, such as allowing modifications to the $at register.

Example:

.set noat  # Allows use of register $at1

Declares an uninitialized data section, typically used for reserving large blocks of memory.

Describes a function's stack frame for debugging tools: base register, stack size and return register. The assembler accepts this metadata directive but does not use it to change program behavior.

Marks the start of a function for debugging tools. The assembler accepts this metadata directive but does not use it to change program behavior.

Marks the end of a function for debugging tools. The assembler accepts this metadata directive but does not use it to change program behavior.

Marks a symbol as local to this file for the linker. This assembler accepts the directive but does not use it to change symbol visibility.

Switches to the named section. In this simulator, .rodata and .bss share the data segment with .data; use .text for instructions.

Example:

.section .rodata
message: .asciiz "Ready"1
2

Declares a section for read-only initialized data, such as string literals. Read-only data is not stored separately in this simulator, so it joins the data segment.

Alias for .rdata.

Alias for .bss.

Reserves bytes for an uninitialized global variable, the way a C compiler declares one. Takes a symbol, a size in bytes and an optional alignment, and leaves the current section unchanged.

Example:

.comm total, 4, 41

Like .comm, but for a symbol local to this file, as a C compiler declares an uninitialized static variable.

Reserves the given number of bytes, which read as zero. Alias for .space.

Alias for .align: aligns the next item on a 2^n byte boundary.

Aligns the next item on the given byte boundary, written directly rather than as a power of two.

Example:

.balign 81

Alias for .half.

Alias for .word.

Alias for .asciiz: stores a null-terminated string.

Alias for .asciiz: stores a null-terminated string.

Alias for .globl.