FreeCalypso > hg > freecalypso-sw

annotate target-utils/libprintf/README @ 992:a7b0b426f9ca

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
target-utils: boot ROM UART autodetection revamped The new implementation should work with both the familiar Calypso C035 boot ROM version found in our regular targets as well as the older Calypso F741979B version found on the vintage D-Sample board.
author Mychaela Falconia <falcon@ivan.Harhan.ORG>
date Wed, 30 Dec 2015 21:28:41 +0000
parents 40f607bb0a2c
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
3
45bf8af5f061 libprintf brought in from older PPC/m68k code, but fucking GCC
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
parents:
diff changeset
1 The present libprintf is a very light printf implementation that is well-suited
45bf8af5f061 libprintf brought in from older PPC/m68k code, but fucking GCC
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
parents:
diff changeset
2 for simple bare-metal programs like loadagent; in the present case it overrides
45bf8af5f061 libprintf brought in from older PPC/m68k code, but fucking GCC
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
parents:
diff changeset
3 the much heavier printf implementation in newlib. Programs like the present
45bf8af5f061 libprintf brought in from older PPC/m68k code, but fucking GCC
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
parents:
diff changeset
4 loadagent only need printf in order to scribble on the serial console port,
45bf8af5f061 libprintf brought in from older PPC/m68k code, but fucking GCC
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
parents:
diff changeset
5 and the most sensible implementation is to have the "character output" function
45bf8af5f061 libprintf brought in from older PPC/m68k code, but fucking GCC
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
parents:
diff changeset
6 from the guts of printf point directly to the physical UART output routine, or
45bf8af5f061 libprintf brought in from older PPC/m68k code, but fucking GCC
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
parents:
diff changeset
7 a trivial wrapper that turns \n into \r\n. In contrast, newlib's version would
45bf8af5f061 libprintf brought in from older PPC/m68k code, but fucking GCC
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
parents:
diff changeset
8 pull in the complete FILE table infrastructure and malloc etc - maybe OK for
45bf8af5f061 libprintf brought in from older PPC/m68k code, but fucking GCC
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
parents:
diff changeset
9 more complex embedded programs that use those facilities for other things under
45bf8af5f061 libprintf brought in from older PPC/m68k code, but fucking GCC
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
parents:
diff changeset
10 a bona fide RTOS, but it would be disgusting to pull that stuff in for a
45bf8af5f061 libprintf brought in from older PPC/m68k code, but fucking GCC
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
parents:
diff changeset
11 minimal program like ours.
45bf8af5f061 libprintf brought in from older PPC/m68k code, but fucking GCC
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
parents:
diff changeset
12
45bf8af5f061 libprintf brought in from older PPC/m68k code, but fucking GCC
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
parents:
diff changeset
13 The present printf implementation has been used earlier by the same author
45bf8af5f061 libprintf brought in from older PPC/m68k code, but fucking GCC
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
parents:
diff changeset
14 (Michael Spacefalcon) in the StarMON family of PowerPC bootloaders, and in my
45bf8af5f061 libprintf brought in from older PPC/m68k code, but fucking GCC
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
parents:
diff changeset
15 MC68x302-based SDSL CPE devices (Hack-o-Rocket and OSDCU).