FunOS Documentation

As of March 8, 2000.

Borrowed Linux Initialization Code

bootsect.S, head.S, then setup.S (with video.S)

• moves loaded init code higher in memory
• read hard drive information
• move kernel (we'll need to write stuff here later)
• enable A20 unit (what's this? I forget.)
• reset coprocessor
• reprogram the interrupts (8259 and 386 interrupt line ranges overlap; bad)
• disable interrupts
• set protected mode bit
• jump into kernel code (the Scheme interpreter (CAML code))

OS Initialization Code

Scheme init code is stored after the interpreter; execute that.

Overview

init-r5rs.scm

R5RS scheme that isn't implemented in CAML code

init-library.scm

generally useful code that we want to assume we always have

devices.scm

general init code for physical devices

console.scm

code for writing information to the screen

keyboard.scm

code for reading data from the keyboard hw and putting it into a useful format

bit-hack.scm

Common Lisp style bit manipulations (dpb, ldb, ...)

word-vectors.scm

reading and writing vectors of data in memory

queues.scm

simple queues (not used)

init-memory.scm

allocating buffers, allocating memory pages

buffer-cache.scm

accesses to disk are cached and written back when dirty. That code is here.

interrupts.scm

dealing with i386 interrupt descriptors (unfinished)

virtual-memory.scm

i386 page tables

squishy.scm

squishy buffers, i.e. emacs-style text buffers (not used)

fs.scm

ext2 filesystem code (unfinished)

init-r5rs.scm

Fix or add syntax and procedures to the Scheme interpreter to make it r5rs compliant.

• cond (built-in cond doesn't handle =>)
• ceiling
• gensym (not r5rs, but earlier than init-library.scm is convenient)
• do
• string->list
• list->string

init-library.scm

Useful library routines

lcond

cond that allows embedded lets. Maybe not a good idea.

(lcond ((null? list) '())
  (let ((top (car list)))
    ((= top y) #t)
     (else (blah (cdr list)))))

destructuring-bind

binds variables to elements of a list or vector.

(destructuring-bind pattern structure body ...)

(destructuring-bind (a b c . d) '(1 2 3 4 5)
  (format #t "~a ~a ~a ~a~%" a b c d))
=> 1 2 3 (4 5)

pattern-match

like destructuring-bind by sequentially tries multiple patterns.

(pattern-match structure (pattern1 body1 ...) ... (else body ...))

dotimes

Do body n times with var bound to that iteration number. Returns result of return-value expression.

(dotimes (var n return-value) body ...)

devices.scm

block and character devices: ide, partitions

low-read-block

(low-read-block device block number)

Read a block from the device.

low-write-block

(low-write-block device block number buffer)

Write the buffer contents into the device.