Quick reference:
| 8 Byte Register | Lower 4 Bytes | Lower 2 Bytes | High Byte | Low Byte |
|---|---|---|---|---|
| rbp | ebp | bp | bpl | |
| rsp | esp | sp | spl | |
| rip | eip | |||
| rax | eax | ax | ah | al |
| rbx | ebx | bx | bh | bl |
| rcx | ecx | cx | ch | cl |
| rdx | edx | dx | dh | dl |
| rsi | esi | si | sil | |
| rdi | edi | di | dil | |
| r8 | r8d | r8w | r8b | |
| r9 | r9d | r9w | r9b | |
| r10 | r10d | r10w | r10b | |
| r11 | r11d | r11w | r11b | |
| r12 | r12d | r12w | r12b | |
| r13 | r13d | r13w | r13b | |
| r14 | r14d | r14w | r14b | |
| r15 | r15d | r15w | r15b |
More complete:
