| ??? 03/03/05 18:04 Read: times |
#89028 - I did not say 7! Responding to: ???'s previous message |
My list is:
AT89S8252 T89C51RD2 DS89C450 P89C51RD+ P89C51RD2H P89V51RD2 All gave 7, except the P89V51RD2, which gave me 8... I also tried 2 rather old DOS-based simulators, both gave 7. This was a pure curiosity. In '86 world, this was a method how to distinguish certain clones. I had seen similar unexpected behaviour also on other processors, where a store-register-pointed-by-same-register-autoincrementing is possible. The reason for 7 is probably as Erik said in some temporary store inside the core. I think that the fact that the V gave 8 while their RDx predecessors gave 7 means that this part has a different core, maybe a different branch of development (maybe the older were still Intel-descendant? maybe Philips found the legacy to be too restrictive in some way?). Compatibility is not an issue here; this is in fact a nonsense operation (similar to mov a,acc - which even does not exist - an exception in design). Jan Waclawek |
| Topic | Author | Date |
| PUSH SP | 01/01/70 00:00 | |
| 8 | 01/01/70 00:00 | |
| 8??????????????????????????????????? | 01/01/70 00:00 | |
| On jokes, reasons &al. | 01/01/70 00:00 | |
| no, you don't | 01/01/70 00:00 | |
| I do not know and do not think I should | 01/01/70 00:00 | |
| Non-compliance? | 01/01/70 00:00 | |
| Theory vs. practice | 01/01/70 00:00 | |
| Jan is right: 7 | 01/01/70 00:00 | |
| I did not say 7! | 01/01/70 00:00 | |
| Interesting | 01/01/70 00:00 | |
| POP SP? :-) | 01/01/70 00:00 | |
| POP SP | 01/01/70 00:00 | |
| MOV SP,#SP | 01/01/70 00:00 | |
| exceptions and rules | 01/01/70 00:00 | |
| MOV A,ACC | 01/01/70 00:00 | |
| xxx a,acc | 01/01/70 00:00 | |
| if the "Bible says"... | 01/01/70 00:00 | |
| more interesting | 01/01/70 00:00 | |
| Hmmm.... interesting indeed! | 01/01/70 00:00 | |
| native doing | 01/01/70 00:00 | |
| Makes sense to me | 01/01/70 00:00 | |
| POP SP | 01/01/70 00:00 | |
| Output of SP | 01/01/70 00:00 | |
| Simulators | 01/01/70 00:00 | |
| simulators give me 7 7 | 01/01/70 00:00 | |
| 7 7 | 01/01/70 00:00 | |
| spent for which purpose | 01/01/70 00:00 | |
| Fun... | 01/01/70 00:00 | |
| Atmel and Philips | 01/01/70 00:00 | |
SiLabs F120 | 01/01/70 00:00 |