DLX instructions

The DLX instruction opcodes are listed in the following three tables. The first table shows the instructions defined in 6-bit opcode field. The second table shows R-R ALU instructions which are defined in the 6-bit function field and have an opcode field of 0. The third table shows the floating-point instructions which are defined in the 6-bit function field and have an opcode field of 1. (In fact, there are 11 bits in function field. Only the least significant 6 bits are used to define both R-R ALU and floating-point instructions.)

Note that, in all tables, each column is numbered by the least significant 3 bits where each row is numbered by the most significant 3 bits. For instance, the opcode of SW is $101011$. Instruction ADD has an opcode $000000$ and a function field $100000$.

All instructions in Table 2 and 3 are R-type. In Table 1, J, JAL, REF, TRAP are J-type, the rest are I-type instructions.

(bit0-2)\(bit3-5) $000$ $001$ $010$ $011$ $100$ $101$ $110$ $111$
$000$ (rr alu) (float) J JAL BEQZ BNEZ BFPT BFPF
$001$ ADDI ADDUI SUBI SUBUI ANDI ORI XORI LHI
$010$ RFE TRAP JR JALR SLLI - SRLI SRAI
$011$ SEQI SNEI SLTI SGTI SLEI SGEI - -
$100$ LB LH - LW LBU LHU LF LD
$101$ SB SH - SW - - SF SD
$110$ - - - - - - - -
$111$ - - - - - - - -

DLX R-R ALU instructions (opcode = 0): only the least-significant 6 bits in the function field are used.

(bit26-28)\(bit29-31) $000$ $001$ $010$ $011$ $100$ $101$ $110$ $111$
$000$ - - - - SLL - SRL SRA
$001$ - - - - - - - -
$010$ - - - - - - - -
$011$ - - - - - - - -
$100$ ADD ADDU SUB SUBU AND OR XOR -
$101$ SEQ SNE SLT SGT SLE SGE - -
$110$ MOVI2S MOVS2I MOVF MOVD MOVFP2I MOVI2FP - -
$111$ - - - - - - - -

DLX floating-poing instructions (opcode = 1): only the least-significant 6 bits in the function field are used.

(bit26-28)\(bit29-31) $000$ $001$ $010$ $011$ $100$ $101$ $110$ $111$
$000$ ADDF SUBF MULTF DIVF ADDD SUBD MULTD DIVD
$001$ CVTF2D CVTF2I CVTD2F CVTD2I CVTI2F CVTI2D MULT DIV
$010$ EQF NEF LTF GTF LEF GEF MULTU DIVU
$011$ EQD NED LTD GTD LED GED - -
$100$ - - - - - - - -
$101$ - - - - - - - -
$110$ - - - - - - - -
$111$ - - - - - - - -