[残卷]RISC-V 指令集

CALCULATE

ADD

• e.g. ADD x1 x0 x0 means x1 = x0 + x0

ADDI

• e.g. ADDI x1 x0 0x11 means x1 = x0 + 3 (DEC)
• The difference is that ADDI is used for numerical, while ADD is used for registers (or variable we can say)
• Normally, we can discover ADDI sp sp -32 at the beginning of the program. It’s used for allocate memory for the main program. sp is the pointer of a stack, use to record the runtime memory stack.

MEMORY

la

• la means load address
• e.g. la x1 VAL VAL’s address is at 0x100, and it’s value is 0x11 then x1 = 0x100
• equal to

lui t0, SYMBOL[31:12]
addi t0, t0, SYMBOL[11:0]

lw

• lw means load word
• e.g. lw x2 VAL causes x2 = 0x11

sw

• sw means save word
• e.g. sw x3 0(x1) will cause x3 = 0x11 and x3 = x2

li

• li means load immediate
• e.g. li a0 VAL means a0 = VAL = 0x114514 for example

the Point is that L means load, S means save. a|b|h|w|d means address, byte, half word, word or double word.

Branch

beq

• beq x1 x2 Label1 means if(x1 == x2) goto Label1

Others

AUIPC

• AUIPC means add an immediate number to pc

• e.g. auipc x28 65536 means