libvm

design.txt

libvm design
------------

Basically Gameboy Z80

registers
=========
[15...8]   [7...0]
[A     ]   [F    ]
[B     ]   [C    ]
[D     ]   [E    ]
[H     ]   [L    ]
[     15...0     ]
[       SP       ]
[       PC       ]

A = Accumulator
F = Flags
SP = Stack Pointer
PC = Program Counter

[Flag Bits             ]
[7][6][5][4][3][2][1][0]
[Z][N][H][C][0][0][0][0]

Z = Zero
N = Negative (Subtract)
H = Half Carry
C = Carry
0 = Unused, Always zero

memory layout
=============

opcodes
=======

d  = immediate 8-bit data
dd = immediate 16-bit data
aa = 16-bit address

-  = untouched
0  = set to zero
1  = set to one

0x00: NOP         [----] [.]
0x01: LD BC, dd   [----] [.DD]
0x02: LD (BC), A  [----] [.]
0x03: INC BC      [----] [.]
0x04: INC B       [Z0H-] [.]
0x05: DEC B       [Z1H-] [.]
0x06: LD B, d     [----] [.d]
0x07:
0x08: LD (aa), SP [----] [.aa]
0x09: ADD HL, BC  [-0HC] [.]
0x0A: LD A, (BC)  [----] [.]
0x0B: DEC BC      [----] [.]
0x0C: INC C       [Z0H-] [.]
0x0D: DEC C       [Z1H-] [.]
0x0E: LD C, d     [----] [.d]
0x0F: