Consider the assembly language function below. I have added some comments to help you understand the code.

(gdb) disas p4

Dump of assembler code for function p4:

0x4005c0 <+0>: movzbl (%rdi),%edx

0x4005c3 <+3>: test %dl,%dl # %dl is the least significant bype of %rdx

0x4005c5 <+5>: je 0x4005e9

0x4005c7 <+7>: add $0x1,%rdi

0x4005cb <+11>: xor %eax,%eax

0x4005cd <+13>: nopl (%rax) # nopl ("no-op") does nothing and is for alignment

0x4005d0 <+16>: cmp %sil,%dl # %sil is the least significant byte of %rsi

0x4005d3 <+19>: sete %dl

0x4005d6 <+22>: add $0x1,%rdi

0x4005da <+26>: movzbl %dl,%edx

0x4005dd <+29>: add %edx,%eax

0x4005df <+31>: movzbl -0x1(%rdi),%edx

0x4005e3 <+35>: test %dl,%dl

0x4005e5 <+37>: jne 0x4005d0

0x4005e7 <+39>: retq

0x4005e9 <+41>: xor %eax,%eax

0x4005eb <+43>: retq

~~~~

What type of data is passed as the second parameter of p4? Explain.