Hmmm (High Speed Move Vram To Vram) - Yamaha V9938 Programmer's Manual

4.4.3. HMMM (High speed move VRAM to VRAM)

HMMM command is used to transfer data from one specific rectangular area in VRAM
of expansion RAM to another area within VRAM of expansion RAM. Note the limitation on
the X coordinate, which is dependent on the current graphics mode (255 or 511).
(SX, SY)
NY
↓
HMMM execution order
Step 1: Set necessary coordinates in command registers
MSB
R#32
R#33
R#34
R#35
R#36
R#37
R#38
R#39
R#40
R#41
R#42
R#43
*In G4 and G6 modes, the lower one bit, and in G5 mode, the lower two bits are lost in registers related to
X-coordinate (DX, NX)
© 1985 ASCII CORP. / NIPPON GAKKI CO.
Video or expansion RAM
NX →
DIY
7 6 5
SX7 SX6 SX5
0 0 0
SY7 SY6 SY5
0 0 0
DX7 DX6 DX5
0 0 0
DY7 DY6 DY5
0 0 0
NX7 NX6 NX5
0 0 0
NY7 NY6 NY5
0 0 0
DIX
(DX, DY)
4 3 2
SX4 SX3 SX2
0 0 0
SY4 SY3 SY2
0 0 0
DX4 DX3 DX2
0 0 0
DY4 DY3 DY2
0 0 0
NX4 NX3 NX2
0 0 0
NY4 NY3 NY2
0 0 0
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1 0 LSB
SX1 SX0 SX*: Source
0 SX8 transfer point X
SY1 SY0 SY: Source
transfer point Y
SY9 SY8
DX1 DX0 DX*:Destination
transfer point X
0 DX8
DY1 DY0 DY: Destination
transfer point Y
DY9 DY8
NX1 NX0 NX*: Number of
dots in x-axis
0 NX8
NY1 NY0 NY: Number of
dots in Y-axis
NY9 NY8
© 2010-2015 Eugeny Brychkov