test results of find_{first,next}_zero_bit find_{first,next}_bit

$ ./a.exe
total bits:128
[31:00]  [63:32]  [95:64]  [127:96]
00000000 00000000 80000000 00000000
next bit: [95 @95
next bit: [32 @95
next bit: [96 @128
[31:00]  [63:32]  [95:64]  [127:96]
00000000 00000000 80000001 ffffffff
zero bit: [65 @65
zero bit: [64 @65
zero bit: [95 @128
[31:00]
00000001
first bit: 0
[31:00]  [63:32]  [95:64]  [127:96]
00000000 00000000 80000000 00000001
first bit: 95
[31:00]  [63:32]
00000000 00000000
first bit: 64
[31:00]  [63:32]
fffffffe fffffffe
first zero bit: 0
[31:00]  [63:32]
ffffffff fffffffe
first zero bit: 32
[31:00]
ffffffff
first zero bit: 32
ffs 80000001:1
ffs 80000000:32
ffs 0:0
ffs 8086:2
ffs 400:11
__ffs 80000001:0
__ffs 80000000:31
__ffs 0:31
__ffs 8086:1
__ffs 400:10
ffz 400:0
ffz ff:8
ffz ffffffff:31