Mab Virtual Machine

Stack Virtual Machine named after Mab - Queen of The Faires

                               .  .  .
                               |\/'\/|
                              .~/_~_\~\.
         /'\                ,//."   "\||\`               /'\
        |   \              '/||<9> <`\\\\|`             /   |
       |  '  `\            /|||   ;  `|\||`           /`  '  |
       |   \   `\__       ,/// \  ~  /`\\||`      __/`   /   |
       \  \   \    `\__   '|||' |` `| '||||'  __/`    /   /  /
       \     '         `\ '|||--'   '--||||'/`   /     '     /
        \    '   "        /'|'         '| \'       "   '    /
         ` \ .......... . ______      . _______ ........ / `         
     . _____      . _____.|    |      |.|      |__________________
    / /     \    / /     \.\   \_______| |    |.|     _______ _    \
   / /   /\  \  / /   /\  \.\    ________     |.|     |______\ \    |
  / /   /. \  \/ /   /. \  \.\   \     | |    |.|     __________   <
 / /   /  . \  \/   /  . \  \.\   \____|.|    |.|     |______/_/    |
|.|____|  |.|_______| |.|______|______________|.|__________________/

Memory Model

A linear array divided in 8x4KiB blocks. Every single block have only one owner indicated with mutex. If a proccess wants to write not own block, block mutex must be locked.

Opcode Model

First 2 bits describes sequence. Other 6 bits describes control and conditional flags.

JUMP	CONTROL FLAGS	CONDITIONAL FLAGS
2-bit	3-bit	3-bit

Assembler Instruction

Each instruction is divided in 3 sections:

• Jump-Sequence Section, starts with :
• Control Flags Section, starts with '
• Conditional Flags Section, starts with "

Syntax

:<S|D|C|V>'[I][E][M]"[L][E][G]

Sequence-Jump Section

code	letter	src (=dst−k)	dst (=src+k)
0x0	S	data src ptr	data src ptr
0x1	D	data dst ptr	data dst ptr
0x2	C	code ptr	code ptr
0x3	V	data src	data dst

Control-Flags Section

code	letter	action	description
0x4	I	k=−k	inverts k
0x8	E	k=k×data[src]; src=src−1	extends k
0x10	M	sleep for locked mutex	locks proccess until write
Indicates mode to execute instruction with 1-3 ordered characters.

Conditional-Flags Section

code	letter	meaning	action	description
0x20	L	lower	src<dst	source is lower than destination
0x40	E	equal	src=dst	source is equal to destination
0x80	G	greater	src>dst	source is greater than destination
Indicates condition to execute instruction with 1-3 ordered characters.