| ??? 03/21/05 06:59 Read: times |
#90077 - why? Responding to: ???'s previous message |
hi,
Payam Soltany said:
We may initialize SP to 1FH or more preferably 2FH (Especially when 20H..2FH is needed for bit banging).
...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? I do not know which IDE/compiler you use, but the general suggestion is: leave this task for compiler and linker/locator. For example, in Keil assembler just do: ; allocate idata memory for stack area ?STACK SEGMENT IDATA RSEG ?STACK STACK: DS 1 ; load stack pointer MOV SP,#(STACK-1)That`s all. The idea is that Keil recognizes ?STACK segment name and places it at the end of all idata segments. As result, you always have all free idata memory used for stack area. I hope other compilers have way like it above. Regards, Oleg |
| 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 |