x86 Assembly convert to C

For a function with prototype long decode2(long x, long y, long z); Gcc generates the following assembly code: 1decode2: subq %rdx, %rsi movq salq sarq xorg ret %rsi, %rax $63 ,%rax $63,%rax %rdi ,%rax Parameters x, y, and z are passed in registers %rdi, %rsi, and %rax. The code stores the return value in register %rax. Write C code for decode2 that will have an effect equivalent to the assembly code shown