Mirror of CollapseOS

Historia

Virgil Dupras 921a109749 stdio: little tweaks		5 vuotta sitten
..
sms	sms/pad: make B jump to the next selection "class"	5 vuotta sitten
README.md	Update docs w.r.t. its relationship with scas	5 vuotta sitten
acia.asm	acia: protect DE during aciaInt	5 vuotta sitten
blockdev.asm	Update comments	5 vuotta sitten
blockdev_cmds.asm	blockdev: fix bug recently introduced in load cmd	5 vuotta sitten
core.asm	shell: add support for backspace	5 vuotta sitten
err.h	blockdev: make implementors "random access"	5 vuotta sitten
fs.asm	zasm: fix include EOF detection	5 vuotta sitten
fs_cmds.asm	fs: fix broken fopn on id > 0	5 vuotta sitten
kbd.asm	kbd: make letters lowercase	5 vuotta sitten
mmap.asm	blockdev: make implementors "random access"	5 vuotta sitten
parse.asm	parse: fix option word default value	5 vuotta sitten
pgm.asm	pgm: adapt to recent blkdev change	5 vuotta sitten
sdc.asm	sdc: make sdcReadBlk return error on max retries	5 vuotta sitten
shell.asm	stdio: add stdioReadC	5 vuotta sitten
stdio.asm	stdio: little tweaks	5 vuotta sitten
user.h.example	zasm emul: bring back kernel/user distinction	5 vuotta sitten

README.md

Kernel

Bits and pieces of code that you can assemble to build a kernel for your machine.

These parts are made to be glued together in a single glue.asm file you write yourself.

This code is designed to be assembled by Collapse OS’ own zasm.

Defines

Each part can have its own constants, but some constant are made to be defined externally. We already have some of those external definitions in platform includes, but we can have more defines than this.

Each part has a “DEFINES” section listing the constant it expects to be defined. Make sure that you have these constants defined before you include the file.

Variable management

Each part can define variables. These variables are defined as addresses in RAM. We know where RAM start from the RAMSTART constant in platform includes, but because those parts are made to be glued together in no pre-defined order, we need a system to align variables from different modules in RAM.

This is why each part that has variable expect a <PARTNAME>_RAMSTART constant to be defined and, in turn, defines a <PARTNAME>_RAMEND constant to carry to the following part.

Thus, code that glue parts together could look like:

MOD1_RAMSTART .equ RAMSTART
#include "mod1.asm"
MOD2_RAMSTART .equ MOD1_RAMEND
#include "mod2.asm"