FreeCalypso > hg > freecalypso-tools
comparison target-utils/libprintf/README @ 0:e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Sat, 11 Jun 2016 00:13:35 +0000 |
| parents | |
| children |
comparison
equal
deleted
inserted
replaced
| -1:000000000000 | 0:e7502631a0f9 |
|---|---|
| 1 The present libprintf is a very light printf implementation that is well-suited | |
| 2 for simple bare-metal programs like loadagent; in the present case it overrides | |
| 3 the much heavier printf implementation in newlib. Programs like the present | |
| 4 loadagent only need printf in order to scribble on the serial console port, | |
| 5 and the most sensible implementation is to have the "character output" function | |
| 6 from the guts of printf point directly to the physical UART output routine, or | |
| 7 a trivial wrapper that turns \n into \r\n. In contrast, newlib's version would | |
| 8 pull in the complete FILE table infrastructure and malloc etc - maybe OK for | |
| 9 more complex embedded programs that use those facilities for other things under | |
| 10 a bona fide RTOS, but it would be disgusting to pull that stuff in for a | |
| 11 minimal program like ours. | |
| 12 | |
| 13 The present printf implementation has been used earlier by the same author | |
| 14 (Michael Spacefalcon) in the StarMON family of PowerPC bootloaders, and in my | |
| 15 MC68x302-based SDSL CPE devices (Hack-o-Rocket and OSDCU). |