or $25,$25,$11 # move opcode into target register
Alternative:
or $25,$11,$0 # move opcode into target register
Recall the instruction we are trying to assemble: ori $8,$9,0x004A
Now
move the bit pattern for the source register $9 into the correct field.
Register $12 contains the pattern in its right-most bits,
as in the first table below.
The pattern should be in bits 25...21 of register $25.
| 31....26 | 25...21 | 20...16 | 15............................0 |
| 000000 | 00000 | 00000 | 0000 0000 0000 1001 |
Here, again, is how the assembled instruction will look when it is finished:
ori $8,$9,0x004A | |||
| 31....26 | 25...21 | 20...16 | 15...................0 |
| 0xD | s | d | unsigned const |
| 0xD | 0x9 | 0x8 | 0x004A |
A sll can be used to move this field into position
as we did for the opcode.
There is a slight problem: the opcode already in $25
must not be erased.