CSE378 Autumn 2003
Miniquiz #3 Solutions

Translate each word of MIPS machine code (given in hex) into an equivalent assembly-language instruction.  Use symbolic names when possible and appropriate.  4 pts. each.

3424000c

ori $4, $1, 12
or
ori $a0, $at, 12

0810001c

j 0x00400070
or
j 4194416

The opcode is 000010, which is j.  The address is formed by taking the other 26 bits: 0x10001c, and shifting them left by 2 (same as multiplying by 4), which you need to do to get the address word-aligned: 0x10001c << 2 = 0x00400070.  The shifting by 2 part can be done quickly by writing out 10001c in binary, then adding two 0 bits at the end (that's what left shift does), then converting the number back to hex.

0000000

sll $0, $0, 0 which is equivalent to nop