Reading Memory

Hi all,
To write and read a word from memory using program buffer,what is the value of "sw s0 0(s1)”?.This is can be a 32-bit instruction or a compressed instruction in the lower 16 bits accompanied by a compressed nop in the upper 16 bits.I had found that the lower 16 bits is “c080” ,than I need add the nop whose value is “0001” into the upper 16 bits.So the whole value of "sw s0 0(s1) is “0001c080”.However it didn’t work.So I would like to ask for some help here,I don’t know where I’ve made a mistake.
Also,I want to know that the Shift-DR of JTAG TAP is higher bit priority or lower bit priority.


If you are just looking for the 32bit opcode for the RV32I instruction sw s0,0(s1)? If so it is the following:0x0084_A023.

The opcode for the compressed version of the sw s0,0(s1) instruction (RV32IC) is as you observed: 0xC080.

I’m not sure i know what you mean by higher or lower bit priority?

Not quite sure what you are asking, but RISC-V ISA is always little endian. As described in the JTAG Standard, the bits are shifted into DR least-significant-bit first. So in the end the word that you would write to program buffer eg:


Should be clocked on TDI in this order:

1 1 0 0 0 1 0 0 ... 0 0 0 1 0 0 0 0 0 0 0 0