Overview of Basic Integer Instructions

This section will describe the functions of application-level basic integer instructions in LA64. For LA32, it only needs to implement a subset of them. The instruction list contained in this subset is shown in the table. Because the length of GR in LA32 is only 32 bits, the sign extension operation in “sign extend the 32-bit result into the general register rd” in the subsequent instruction description is not required.

Table 1. Application-level basic integer instructions in LA32

Arithmetic operation instructions	`ADD.W, SUB.W, ADDIW, ALSL.W, LU12L.W, SLT, SLTU, SLTI, SLTUI,` `PCADDI, PCADDU12I, PCALAU12I,` `AND, OR, NOR, XOR, ANDN, ORN, ANDI, ORI, XORI,` `MUL.W, MULH.W, MULH.WU, DIV.W, MOD.W, DIV.WU, MOD.WU`
Bit-shift instructions	`SLL.W, SRL.W, SRA.W, ROTR.W, SLLI.W, SRLI.W, SRAI.W, ROTRI.W`
Bit-manipulation instructions	`EXT.W.B, EXT.W.H, CLO.W, CLZ.W, CTO.W, CTZ.W, BYTEPICK.W,` `REVB.2H, BITREV.4B, BITREV.W, BSTRINS.W, BSTRPICK.W, MASKEQZ, MASKNEZ`
Branch instructions	`BEQ, BNE, BLT, BGE, BLTU, BGEU, BEQZ, BNEZ, B, BL, JIRL`
Memory access instructions	`LD.B, LD.H, LD.W, LD.BU, LD.HU, ST.B, ST.H, STW, PRELD`
Atomic memory access instructions	`LL.W, SC.W`
Barrier instructions	`DBAR, IBAR`
Other instructions	`SYSCALL, BREAK, RDTIMEL.W, RDTIMEH.W, CPUCFG`

In addition, for those instructions whose data length of the operation object is GR length, the operation length is 32 bits in LA32 and 64 bits in LA64. Unless there are special circumstances, no special instructions will be given in the instruction function description.