| ??? 06/21/11 23:19 Read: times |
#182704 - Re: XCHD use Responding to: ???'s previous message |
Erik Malund said:
looking for something else I happened to see XCHD and realized that after ages working with the '51 I did not remember that instruction even existed. I realized I had never used it and started to wonder. I came up with two questions
1) have you ever used this instruction, if so for what 2) what might be the reason the original designers of the '51 spent (wasted) an instruction on this exotic thing Erik Hi Erik, 1.) Most recently for my Flea86 project - several 16-color modes would not have been possible without the XCHD instruction.. 2.) My guess is it also serves as a (albeit destructive) '4-bit MOV instruction' equivalent, though careful planning is required beforehand to make it work in this manner.. Regards Valentin |
| Topic | Author | Date |
| XCHD use | 01/01/70 00:00 | |
| XCHG usage | 01/01/70 00:00 | |
| Search... | 01/01/70 00:00 | |
| Re: XCHD use | 01/01/70 00:00 | |
| not generated | 01/01/70 00:00 | |
| SDCC might add pBCD type of numbers | 01/01/70 00:00 | |
| Not a good idea | 01/01/70 00:00 | |
| Depends | 01/01/70 00:00 | |
| You're right | 01/01/70 00:00 | |
| another possibility ... | 01/01/70 00:00 | |
| both: 8048 legacy + (packed) BCD | 01/01/70 00:00 | |
simple example | 01/01/70 00:00 |