FreeCalypso > hg > freecalypso-sw
comparison loadagent/libprintf/README @ 3:45bf8af5f061
libprintf brought in from older PPC/m68k code, but fucking GCC
refuses to compile <varargs.h> - need to convert to Anshit C <stdarg.h>
| author | Michael Spacefalcon <msokolov@ivan.Harhan.ORG> |
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| date | Mon, 29 Apr 2013 07:00:22 +0000 |
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| 2:ddda170fa6f4 | 3:45bf8af5f061 |
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| 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). |