What is the assembly code doing? (Hint: Recursion)

Dump of assembler code for function func4: => 0x0000000000400fe2 : $0x8,%rsp %edx, %eax %esi,%eax %eax, %ecx $0x1f, secx %ecx, %eax %eax (%rax , % rsi,1),%ecx 0x0000000000400fe6 : 0x0000000000400fe8 : 0x0000000000400fec : 0x0000000000400fef 0x0000000000400ff1 ; 0x0000000000400ff3 : 0x0000000000400ff6 : cmp %edi,%ecx 0x0000000000400ff8 : jle 0x401006 0x0000000000400ffa 0x000000000040ffd : callq 0x400fe2 0x0000000000401002 +32> : 0x0000000000401004 :jmp0x40101b : 0x000000000040100b : 0x000000000040100d ; 0x0000000000401012 : callq 0x400fe2 0x0000000000401017 mov sub mov shr add sar lea lea -0x1 ( %rcx),%edx %eax, %eax $0x8, %eax add mov cmp lea lea retq %edi, %ecx 0x1 ( %rcx),%esi 0x1(srax,srax,1),seax End of assembler dump (gdb) Dump of assembler code for function func4: => 0x0000000000400fe2 : $0x8,%rsp %edx, %eax %esi,%eax %eax, %ecx $0x1f, secx %ecx, %eax %eax (%rax , % rsi,1),%ecx 0x0000000000400fe6 : 0x0000000000400fe8 : 0x0000000000400fec : 0x0000000000400fef 0x0000000000400ff1 ; 0x0000000000400ff3 : 0x0000000000400ff6 : cmp %edi,%ecx 0x0000000000400ff8 : jle 0x401006 0x0000000000400ffa 0x000000000040ffd : callq 0x400fe2 0x0000000000401002 +32> : 0x0000000000401004 :jmp0x40101b : 0x000000000040100b : 0x000000000040100d ; 0x0000000000401012 : callq 0x400fe2 0x0000000000401017 mov sub mov shr add sar lea lea -0x1 ( %rcx),%edx %eax, %eax $0x8, %eax add mov cmp lea lea retq %edi, %ecx 0x1 ( %rcx),%esi 0x1(srax,srax,1),seax End of assembler dump (gdb)