software/

Programs for the P32W itself.

cmd/	the P32W Unix commands (C): init, sh, ls, cat, cp, mv, rm, ln, mkdir, rmdir, pwd, grep, wc, sort, uniq, head, tail, tee, ps, kill, chmod, chown, date, stty, halt, ...
libc/, include/	the C library (M2, D22): strings, ctype, malloc, stdio / printf, stdlib, setjmp, system calls, signals, directories, time
sa/crt0_sa.s	the stand-alone runtime: C programs on the bare machine (the compiler's tests)
root.manifest	the root filesystem: what make disk puts where
tests/	scripted P32W Unix sessions (run_session.sh, in make test)
monitor/monitor.asm	the boot ROM monitor — the first program at reset: console on UART 0 (9600 8N1); dump and modify memory, call a program, load sectors from the CompactFlash card, boot from it; catches exceptions and reports them
lib/p32io.inc	UART, CompactFlash and port routines (the programmer's guide's)

make builds the library and the commands; make disk builds build/disk.img: the kernel (kernel/) in the boot area and the root filesystem (tools/p32fs.py build). Boot it with the monitor's b.

The monitor and the library are tested by make test on both emulators: emulator/test/lib_test.asm exercises the library; a scripted monitor session boots a program from a disk image and must match emulator/test/monitor.expect exactly.

The monitor

python3 assembler/p32asm.py software/monitor/monitor.asm -o monitor.bin
python3 emulator/test/mkbootdisk.py program.bin disk.img     # a bootable disk
emulator/p32emu -d disk.img monitor.bin                     # try it

Command
d ADDR [LEN]	dump memory as words (hex; default 16 bytes)
m ADDR VALUE	store a word
g ADDR	call a program; it may RET to the monitor, which shows its r1
l LBA COUNT ADDR	load sectors from the card
b	boot: sector 0 holds "P32B", the sector count, the load address and the entry point; sectors 1.. hold the program
? / q	help / HALT

An exception (a bad address, an illegal instruction in a called program) prints CAUSE, EPC and BADADDR and returns to the prompt: the monitor sets VBR to its own handler. It keeps its line buffer and stack at 0x001F_FC00 down, at the top of the first 2 MiB bank (which every machine has, D60), so programs have 0x0010_0000–0x001F_7FFF.

On the hardware the monitor's image is what goes into the boot ROM: split into byte lanes for the four flash chips (or written in place by the debug card's host link with the PROG jumper fitted).