| ??? 03/29/05 22:37 Read: times |
#90639 - Hitting the Wall Responding to: ???'s previous message |
James Hinnant said:
and re the C list, it is somewhat overstated. coding applications in C is OK on lower-performance systems, but if you hit a wall with RAM or performance you will need to upgrade or probably convert to assembly for optimization. the project i was working on used a radiation-hardened 8052 for space environments, no onboard or offboard RAM except for the 256 bytes of chip RAM, no upgrade processor available, no hardware design changes available to help the code. so i was stuck, and probably most projects would not get stuck in that way. I think there are plenty of other examples where different criteria lead to a similar situation. I spent most of my career developing very high volume microcontroller based products where every cent of the bill of materials was important. Upgrading to a micro 10 cents more expensive costs $100,000 when you make a million units. This naturaly leads to minimal RAM and ROM resources being available. We did several versions of a CO detector which had 2K of code, met UK and US detection standards and ran for 5 years on one battery. IIRC 800,000 were made in the first couple of years. Ian |
| Topic | Author | Date |
| 8051 in C or assembly? | 01/01/70 00:00 | |
| Probably C | 01/01/70 00:00 | |
| Always C | 01/01/70 00:00 | |
| Mostly 'C' | 01/01/70 00:00 | |
| No magic wand | 01/01/70 00:00 | |
| Assembler when? | 01/01/70 00:00 | |
| Shared data problem?? | 01/01/70 00:00 | |
| Shared Data Problem | 01/01/70 00:00 | |
| I see | 01/01/70 00:00 | |
| Sared Data | 01/01/70 00:00 | |
| addendum | 01/01/70 00:00 | |
| Shared Data | 01/01/70 00:00 | |
| Knowledge, not language. | 01/01/70 00:00 | |
| Knowledge | 01/01/70 00:00 | |
| Knowledge | 01/01/70 00:00 | |
| Promotion | 01/01/70 00:00 | |
| Promotion | 01/01/70 00:00 | |
| Promotion | 01/01/70 00:00 | |
| Traps for the unwary | 01/01/70 00:00 | |
| Preaching | 01/01/70 00:00 | |
| Ditto | 01/01/70 00:00 | |
| red rag.... | 01/01/70 00:00 | |
Bend over then... | 01/01/70 00:00 | |
| hauling assembler | 01/01/70 00:00 | |
| Clarification | 01/01/70 00:00 | |
| Keil Allows this to be disabled | 01/01/70 00:00 | |
| Know your tools | 01/01/70 00:00 | |
| It means 8 bit may be 16 bits | 01/01/70 00:00 | |
| More knowledge! | 01/01/70 00:00 | |
| not really | 01/01/70 00:00 | |
| So which... | 01/01/70 00:00 | |
| Calculations in C | 01/01/70 00:00 | |
| ibid | 01/01/70 00:00 | |
| Not always.. | 01/01/70 00:00 | |
| Example | 01/01/70 00:00 | |
| Better?? | 01/01/70 00:00 | |
| assembly | 01/01/70 00:00 | |
| YMMV | 01/01/70 00:00 | |
| assembly | 01/01/70 00:00 | |
| Hitting the Wall | 01/01/70 00:00 |