mirror of
https://github.com/hsoft/collapseos.git
synced 2024-11-06 03:10:54 +11:00
cd514e6cd6
Also, fix (roll) which wasn't properly implemented.
17 lines
611 B
Plaintext
17 lines
611 B
Plaintext
PC/AT Recipe
|
|
|
|
Work in progress.
|
|
|
|
Register usage: SP is PSP, BP is RSP, DX is IP
|
|
|
|
Unlike z80 boot code, we don't check PS at each next call (we
|
|
do check RS though). It is the responsibility of every native
|
|
PSP-modifying word to call chkPS, . Also, chkPS, is a bit
|
|
different than in z80: it is parametrizable. The idea is that
|
|
we always call chkPS, before popping, telling the expected size
|
|
of stack. This allows for some interesting optimization. For
|
|
example, in SWAP, no need to pop, chkPS, then push, we can
|
|
chkPS and then proceed to optimized swapping in PS.
|
|
|
|
811 MBR bootloader 812-829 Boot code
|