arch_docs.txt

Number of bits: description

GPU main
========

[fOoopcc1111ccbbuu2222ttttwwww]
[87777666655554444333322221111]
[18421842184218421842184218421]

physical truthtable order:
10, 00, 11, 01

instruction truthtable order:
00, 01, 10, 11

4: write register
4: op truthtable

2: reg1 coreshift mode
	0x = no coreshift
	10 = coreshift left
	11 = coreshift right
2: reg1 bitshift mode
	00 = no bitshift
	01 = set random (nothing to do with bitshift)
	10 = bitshift left
	11 = bitshift right
4: reg1 reg id

2: reg2 regmode
regmode = 0x (reg):
	4: reg id
regmode = 10 (uniform across-core):
regmode = 11 (uniform in-core):
	4: reg id

2: colour channel (0 = no update)
1: flush screen buffer

total: 25

GPU controller
==============

6: opcode (only 5 bits used)
1: update flags/graphics buffer

opcode = 00000 to 00001 (generics):
	same as CPU
opcode = 00100 to 00110 (jmps):
	same as CPU
opcode = 01000 (or graphics buffer):
opcode = 01001 (and graphics buffer):
	4: write reg
opcode = 01010 (read buffer in-core axis):
opcode = 01011 (read buffer across-core axis):
	4: write reg
	18: immreg position
opcode = 01100 to 01111 (bitwise ops):
	same as CPU
opcode = 10000 to 10101 (devices and interrupts):
	same as CPU
opcode = 11xxx (gpu):
	1: update graphics buffer
	25: command

CPU
===

Special registers:
	1110: SP
	1111: XP

ARITH:
[ooooouffff21111122222222ddddd]
Jcc:
[ooooooffff___ir_jjjjjjjjjjjjj]
JAL
[ooooooddddd__irfjjjjjjjjjjjjj]
BOOL
[oooooocccc_____f________ddddd]
LOOP
[oooooossssscccccsjjjjjjjjjjjj]
MEM
[ooooooffffobbbbbboooooo_ddddd]
MEML
[ooooooffffwwwwwwwwwwwwwwddddd]
MEMC
[ooooooffffrwwwwwwwwwwwwwaaaaa]
STACK
[ooooooffffv_____vvvvv___ddddd]
FUNC
[ooooooffff______jjjjjjjjjjjjj]


6: opcode

opcode = MISC:
	1: clear PC
	1: suspend

opcode = MOVH
opcode = MOVL:
	5: dest
	1: clear other bits
	1: clear bits to
	16: val

opcode = ARITH:
opcode = ARITH_NOUPDATE: // don't update flags
	4: func

	func = ADD:
	func = SUB:
	func = ADDC:
	func = SUBB:

	func = SHL:
	func = SHR:
	func = SRA:
	// same as SHL but with registers swapped. optional.
	func = RSHL:

	func = AND:
	func = OR:
	func = XOR
	func = MASK:
	
	func = SET:
	func = UNSET:
	func = ISSET:
	func = NOTSET: // whole block optional
		5: dest
		5: reg1 // with sign extension
		9: immreg2 // with sign extension

opcode = Jcc:
	4: func
	
	func = JMP:
	func = JZ:
	func = JNZ:

	func = JN:
	func = JNN:
	func = JP:
	func = JNP:

	func = JC:
	func = JNC:
	func = JO:
	func = JNO:
		1: mask interrupts
		1: not relative to PC
		13: immreg jump dest

opcode = JAL/BOOL:
	5: dest
	1: func

	func = JAL:
		1: mask interrupts
		1: not relative to PC
		13: immreg jump dest
	
	func = BOOL: // optional
		4: condition // same as Jcc func

opcode = LOOP: // optional
	5: condition reg
	6: immreg step
	12: imm jump dest (relative) // with sign extension

opcode = MEM:
opcode = MEM_NOUPDATE: // don't update flags
	4: func

	func = LOAD:
	func = STORE:
		5: dest/writeVal
		6: immreg base
		1: override base with PC // optional
		6: immreg offset // optional
	
	func = LDL:
	func = STL: // long addresses. optional.
		5: dest/writeVal
		14: imm addr
	
	func = STC:
	func = STRC: // optional
		5: addr
		1: relative to PC or SP // for STRC
		13: immreg writeVal // with sign extension

opcode = STACK:
opcode = STACK_NOUPDATE:
	4: func

	func = PUSH:
		9: immreg val
	
	func = POP:
		5: dest
	
	func = CALL:
		13: immreg jump dest
	
	func = RET:
		
CPU (old)
=========

[fOooooorrrrisiiiiiiiiiiiiiiii]
[87777666655554444333322221111]
[18421842184218421842184218421]

immreg (18):
	1: immediate or reg
	imm:
		1: sign
		16: immediate
	reg:
		4: reg id

ramimmreg (11):
	1: immediate or reg
	imm:
		10: immediate
	reg:
		4: reg id

Special registers:
	1110: LP
	1111: XP

6: opcode (only 5 bits used)

opcode = MISC:
	1: clear PC
	1: suspend

opcode = JMP:
	1: update LP
	1: mask interrupts (ignored if relative)
	1: relative jmp
	4: jmp condition
	jmp condition:
		0000: unconditional
		0001: never
		0100: is negative
		0101: not negative
		0110: is positive
		0111: not positive
		1000: carry
		1001: not carry
		1010: overflow
		1011: not overflow
		1100: is zero
		1101: not zero
	11: ramimmreg addr
opcode = LOOP:
	1: update LP
	1: relative jmp
	4: loop condition reg
	1: custom step
	4: step reg
	12: ramimmreg addr

opcode = BOOL:
	4: write reg
	4: condition (same as jmp condition)

opcode = LOAD:
	4: write reg
	18: immreg addr
opcode = STORE:
	4: write val reg
	18: immreg addr
opcode = SEND:
	4: addr reg
	18: immreg write val

opcode = LDR:
	4: write reg
	4: offset reg
	1: use PC
	11: ramimmreg base addr
opcode = STR:
	4: write val reg
	4: offset reg
	1: use PC
	11: ramimmreg base addr

opcode = PUSH:
	4: SP reg
	18: immreg push val
opcode = POP:
	4: SP reg
	4: write reg
opcode = CALL:
	1: update LP
	4: SP reg
	11: ramimmreg addr
opcode = RET:
	1: update LP
	4: SP reg

opcode = MOV:
opcode = ADD:
opcode = SUB:
opcdoe = ADDC:
opcode = SUBB:
opcode = SHL:
opcode = SHR:
opcode = SRA:
opcode = LSB:
opcode = AND:
opcode = OR:
opcode = MASK:
opcode = XOR:
	1: update flags
	4: arg1/write reg
	18: immreg arg2

Memory Map
==========
0x000 - 0xFFF: Main RAM
0x1000 - 0x103F: Interrupt vector table
0x1040 - 0x107F: Trigger interrupt (write-only)
0x1080 - 0x1083: Interrupt mask register (4 * 16-bit)
0x1084: Processor flags
0x1085: IP (read-only)
0x1200 - 0x13FF: GPU shader RAM
0x1400 - 0x140F: GPU uniforms (write-only)
0x1410 - 0x141F: GPU graphics buffer in-core axis (read-only)
0x1420 - 0x141F: GPU graphics buffer across-core axis (read-only)
0x1430 - 0x143F: GPU graphics buffer ops (read-only)
0x1440: GPU controller inject
0x1800 - 0x180F: Text display (write-only)
0x1810 - 0x181F: Icon display (write-only)
0x1820 - 0x182F: Touchscreen touch buffer
0x1830 - 0x183F: Keyboard buffer
0x1900 - 0x19FF: Reserved IO
0x2000 - 0x3FFF: Reserved for hard drive

Interrupts
==========
0x0 - 0xF: Processor interrupts
0x10 - 0x1F: Software interrupts
	0x10: Cross GPU/CPU interrupt
0x20 - 0x3F: Device interrupts
	0x20: Touchscreen interrupt
	0x21: Keyboard interrupt

Flags
=====

- Zero flag
- Negative flag
- Carry flag
- Overflow flag
- Interrupts masked flag

Text Display Control Characters
===============================

Hardware control bits
---------------------

0: Print on line 1
1: Print on line 2
2: Backspace on line 1
3: Backspace on line 2
4: Clear line 1
5: Clear line 2
6: Push line 2 up

ASCII (7-bit encoding)
----------------------

0x0 (Null): Do nothing
0x1 (Start of heading): Set first line as current line
0x2 (Start of text): Set second line as current line
0x4 (End of transmission): Cut short 4-word decoding
0x7 (Bell): Flash LED
0x8 (Backspace): Clear one character from current line
0xA (New line): If first line is current line, clear second line and set second line as current line; if second line is current line, clear first line and push second line up
0xC (New page): Clear both lines and set first line as current line
0xD (Carriage return): Delete current line
0x11 - 0x14 (Device control) and beyond: Change font colour
0x7F (Delete): Filled rectangle character