FreeCalypso > hg > freecalypso-tools
annotate target-utils/libprintf/README @ 696:dbbafb1f33f3
loadtools/fldevs.c: removed unnecessary #include headers
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Wed, 11 Mar 2020 18:24:11 +0000 |
parents | e7502631a0f9 |
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rev | line source |
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e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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1 The present libprintf is a very light printf implementation that is well-suited |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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2 for simple bare-metal programs like loadagent; in the present case it overrides |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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3 the much heavier printf implementation in newlib. Programs like the present |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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4 loadagent only need printf in order to scribble on the serial console port, |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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5 and the most sensible implementation is to have the "character output" function |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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6 from the guts of printf point directly to the physical UART output routine, or |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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7 a trivial wrapper that turns \n into \r\n. In contrast, newlib's version would |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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8 pull in the complete FILE table infrastructure and malloc etc - maybe OK for |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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9 more complex embedded programs that use those facilities for other things under |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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10 a bona fide RTOS, but it would be disgusting to pull that stuff in for a |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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11 minimal program like ours. |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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12 |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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13 The present printf implementation has been used earlier by the same author |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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14 (Michael Spacefalcon) in the StarMON family of PowerPC bootloaders, and in my |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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15 MC68x302-based SDSL CPE devices (Hack-o-Rocket and OSDCU). |