Convert the following assembly code from gcc to a C function which does the same thing. C function should take three parameters: a,b,c. a is passed in rdi , b in rsi and c in rdx and the return value stored in rax.

decode: subq %rdi, %rsi imulq %rsi, %rdi movq %rsi, %rax salq $63, %rax sarq $63, %rax xor %rdi, %rax ret