| ??? 03/21/05 06:28 Read: times |
#90075 - initializing SP to 7FH |
We may initialize SP to 1FH or more preferably 2FH (Especially when 20H..2FH is needed for bit banging). In Intel's MCS-51 User's Manual page 8 figure 8, we have the phrase: "The Upper 128 Bytes... available as stack in devices with 256-bytes RAM". It seems to me that while using 256 byte clones when we needn't have more than some 128 bytes of internal RAM, it's a good practice to initialize SP to 7FH as suggested by Intel and thus "get rid of" indirectly addressing internal RAM(Upper 128), meanwhile freeing the lower 128 as an "easier" way of RAMing. What do you think?
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| Topic | Author | Date |
| initializing SP to 7FH | 01/01/70 00:00 | |
| why? | 01/01/70 00:00 | |
| To Oleg & Russell | 01/01/70 00:00 | |
| To Mehdi | 01/01/70 00:00 | |
| To Mehdi | 01/01/70 00:00 | |
| why not | 01/01/70 00:00 | |
| for example, please | 01/01/70 00:00 | |
| Oleg, why I do similar | 01/01/70 00:00 | |
| here they are | 01/01/70 00:00 | |
| well | 01/01/70 00:00 | |
| well well | 01/01/70 00:00 | |
| well, well - done | 01/01/70 00:00 | |
| tight SRAM - use C | 01/01/70 00:00 | |
- or assembler | 01/01/70 00:00 | |
| Stack pointer | 01/01/70 00:00 | |
| external stack | 01/01/70 00:00 | |
| why not? | 01/01/70 00:00 | |
| SDCC | 01/01/70 00:00 | |
| Re:initializing SP to 7FH | 01/01/70 00:00 | |
| very old assemblers only | 01/01/70 00:00 | |
| Let the assembler do the work! | 01/01/70 00:00 |