From 97e6d8f66aa4589d40e4a449d5b2753080534387 Mon Sep 17 00:00:00 2001 From: David Given Date: Sun, 16 Jun 2019 20:10:13 +0200 Subject: [PATCH] Update README. --- plat/cpm/README | 24 ++++++++++-------------- 1 file changed, 10 insertions(+), 14 deletions(-) diff --git a/plat/cpm/README b/plat/cpm/README index c7d7b1ac4..a774d0d50 100644 --- a/plat/cpm/README +++ b/plat/cpm/README @@ -1,26 +1,22 @@ -# $Source$ -# $State$ -# $Revision$ - - The cpm platform ================= cpm is an i80-based BSP that generates CP/M executables that can be run on any CP/M-compliant machine. -This port only implements a very limited set of syscalls --- and most of those -are stubs required to make the demo apps link. File descriptors 0, 1 and 2 -represent the console. Each read() blocks and reads an entire line (it can't -read part of a line) from the CP/M line editor, then appends \n. Each write() -converts \n to \r\n. The line editor and \n conversion can't be turned off. +CP/M has special needs in many ways, the main one being that it doesn't +support byte-accessible files --- only complete 128-byte sectors can be read +or written. The port's read/write/open/close/lseek etc should handle this +transparently, but trying to write a fragment of a sector will involve a +read/modify/write cycle. No buffering is done (that's stdio's job). -There's a special, if rather minimilist, interface to give applications access +File descriptors 0, 1 and 2 represent the console, as usual. + +In addition, there's a special interface to give applications direct access to CP/M. See include/cpm.h for details. -Link with `ack -fp` to enable software floating point. Otherwise, attempts to -use floating-point numbers will cause the program to terminate. - +Floating point is not supported and attempts to use floating-point numbers +will cause the program to terminate. Example command line ====================