diff 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
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/target-utils/libprintf/README	Sat Jun 11 00:13:35 2016 +0000
@@ -0,0 +1,15 @@
+The present libprintf is a very light printf implementation that is well-suited
+for simple bare-metal programs like loadagent; in the present case it overrides
+the much heavier printf implementation in newlib.  Programs like the present
+loadagent only need printf in order to scribble on the serial console port,
+and the most sensible implementation is to have the "character output" function
+from the guts of printf point directly to the physical UART output routine, or
+a trivial wrapper that turns \n into \r\n.  In contrast, newlib's version would
+pull in the complete FILE table infrastructure and malloc etc - maybe OK for
+more complex embedded programs that use those facilities for other things under
+a bona fide RTOS, but it would be disgusting to pull that stuff in for a
+minimal program like ours.
+
+The present printf implementation has been used earlier by the same author
+(Michael Spacefalcon) in the StarMON family of PowerPC bootloaders, and in my
+MC68x302-based SDSL CPE devices (Hack-o-Rocket and OSDCU).