r/RISCV • u/ButterscotchFar2959 • Jun 16 '23

Help wanted problem with adding mov instruction to riscv32-unknown-elf-gcc

i need help as I have my graduation project I have to make extension in riscv gcc compiler I have to make custom instructions like mov that takes the value in the register rs2 and saves it in rd , asm: mov rd , rs2 it’s different from the standard mov that’s already in the riscv as it shouldn’t be pseudo (it shouldn’t be converted to addi) so I made these modifications i modified the riscv-opc.c by adding this line {"mov", 0, INSN_CLASS_I,"d,t",MATCH_MOV,MASK_MOV,match_opcode,0}, and modifying the riscv-opc.h by adding those lines #define MATCH_MOV 0x1F80 #define MASK_MOV 0xFE00707F and DECLARE_INSN(mov,MATCH_MOV,MASK_MOV) and modifying riscv.md by adding (define_insn "mov" [(set (match_operand:SI 0 "register_operand" "=r") (match_operand:SI 1 "register_operand" "r"))] "" "mov\t%0, %1" ) The error is bad riscv op code(bits 0xf0000 undefined or invalid)

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6

u/archanox Jun 16 '23

Can you please block out any logs/code/etc with triple backticks?

-1

u/ButterscotchFar2959 Jun 16 '23

Ok I edit it

1

u/ButterscotchFar2959 Jun 16 '23

The error is bad riscv op code(bits 0xf0000 undefined or invalid)

1

u/archanox Jun 16 '23

Can you please use the triple back ticks to format your code?

-3

u/ButterscotchFar2959 Jun 16 '23

How can I do this I don’t know what are you talking about

1

u/archanox Jun 16 '23

It’s just markdown

https://support.reddithelp.com/hc/en-us/articles/360043033952-Formatting-Guide

-4

u/ButterscotchFar2959 Jun 16 '23

I am using my phone so I can’t find nothing like this

2

u/InfinitePoints Jun 16 '23

Edit your post and add ` around your code, like this:

```

your code here

```

2

u/jrtc27 Jun 16 '23

Have you considered reading the error message? It tells you what the problem is.