MIPS assembler directives
(From Computer Organization and Design - The Hardware/Software Interface by Dave Patterson and John Hennessy, 2nd edition)
SPIM supports a subset of the assembler directives provided by the actual MIPS assembler:
| .align n |
Align the next datum on a 2n byte boundary.For example, .align 2 aligns the next value on a word boundary. .align 0 turns off automatic alignment of .half, .word, .float, and .double directives until the next .data or .kdata directive. |
| .ascii str | Store the string in memory, but do not null-terminate it. |
| .asciiz str | Store the string in memory and null-terminate it. |
| .byte b1,..., bn | Store the n values in successive bytes of memory. |
| .data <addr> |
The following data items should be stored in the data segment. If the optional argument addr is present, the items are stored beginning at address addr. |
| .double d1,..., dn |
Store the n floating point double precision numbers in successive memory locations. |
| .extern sym size |
Declare that the datum stored at sym is size bytes large and is a global symbol. This directive enables the assembler to store the datum in a portion of the data segment that is efficiently accessed via register $gp. |
| .float f1,..., fn |
Store the n floating point single precision numbers in successive memory locations. |
| .globl sym |
Declare that symbol sym is global and can be referenced from other files. |
| .half h1,..., hn | Store the n 16-bit quantities in successive memory halfwords. |
| .kdata <addr> |
The following data items should be stored in the kernel data segment. If the optional argument addr is present, the items are stored beginning at address addr. |
| .ktext <addr> |
The next items are put in the kernel text segment. In SPIM, these items may only be instructions or words (see the .word directive below). If the optional argument addr is present, the items are stored beginning at address addr. |
| .space n |
Allocate n bytes of space in the current segment (which must be the data segment in SPIM). |
| .text <addr> |
The next items are put in the user text segment. In SPIM, these items may only be instructions or words (see the .word directive below). If the optional argument addr is present, the items are stored beginning at address addr. |
| .word w1,..., wn |
Store the n 32-bit quantities in successive memory words. SPIM does not distinguish various parts of the data segment (.data, .rdata and .sdata). |