RISC-V Instruction

Risc-V 指令一览

Risc-V Instructions

I instructions

add		dst, src1, src2
addi 	dst, src1, imm
sub 	dst, src1, src2

lw 		reg, off(addr)
lh 		reg, off(addr)
lhu		reg, off(addr)
lb		reg, off(addr)
lbu		reg, off(addr)
sw 		reg, off(addr)
sh		reg, off(addr)
sb		reg, off(addr)

beq		reg1, reg2, label		; reg1 == reg2
bne 	reg1, reg2, label		; reg1 != reg2
blt		reg1, reg2, label		; reg1 < reg2
bgt 	reg1, reg2, label		; reg1 > reg2
ble		reg1, reg2, label		; reg1 <= reg2
bge		reg1, reg2, label		; reg1 >= reg2

sll		dst, src1, src2			; shift left logical
slli	dst, src, imm
srl		dst, src1, src2			; shift right logical
srli 	dst, src, imm
sra		dst, src1, src2			; shift right arithmetic
sra		dst, src, imm

mul 	dst, scr1, src2
mulh	dst, src1, src2
div 	dst, src1, scr2
rem		dst, src1, src2

and 	dst, src1, src2
andi 	dst, src, imm
or 		dst, src1, src2
ori		dst, src, imm
xor		dst, src1, src2
xori	dst, src, imm

slt		dst, reg1, reg2			; dst = reg1 < reg2 ? 1 : 0
slti	dst, reg, imm			; dst = reg < imm ? 1 : 0

ecall

ecall

a0	name	description
1	print int	print integer in a1
4	print string	print the string whose address in a1
9	sbrk	allocates a1 bytes on heap, return start pointer in a0
10	exit	ends the program
11	print character	print ascii character in a1
13	open file	a1:file path, a2:permission bits, rerurn fd in a0
14	read file	a1:fd, a2:buffer, a3:bytes, return a0:read bytes num
15	write file	a1:fd, a2:buffer, a3:bytes, return a0:write bytes num
16	close file	a1:fd, return a0:0 success, -1 eof
17	exit2	ends the program with return code in a1
18	fflush	a1:fd, return a0:0 success, -1 eof
19	feof	a1:fd, reached eof, return a0:0, otherwise other value
20	ferror	a1:fd, no error, return a0:0, otherwise nonzero value
34	print hex	print hex in a1
0x3cc	vlib

a6	name	description
1	malloc	a1:size, return a0:block pointer
2	calloc	a1:n items, a2:each size, return a0:block pointer
3	realloc	a1:block pointer, a2:resize, return a0:new pointer
4	free	a1:block pointer
5	num alloc blocks	return a0:number of nonfree blocks, -1 error

Pseudo Instructions

mv		dst, reg		; addi
li 		dst, imm		; addi lui
la 		dst, label		; auipc
nop						; addi
neg		dst, reg		; sub
not 	dst, reg		; xori
beqz	reg, label		; beq

Function

j label					; jump
jal dst, label			; jump and link
jalr dst, src, imm		; jump and link register
jr ra					; jump register (ret)