Lmcm (Logical Move Vram To Cpu) - Yamaha V9938 Programmer's Manual

4.4.6. LMCM (Logical move VRAM to CPU)

LMCM command is used to transfer data from the video or expansion RAM in a
specified rectangular area to the CPU through VDP. The units used are dots.
CPU
LMCM execution order
Step 1: Set necessary coordinates in command registers
MSB
R#32
R#33
R#34
R#35
R#40
R#41
R#42
R#43
Step 2: Select source memory and direction from base coordinate
MSB
R#45
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VDP
7 6 5
SX7 SX6 SX5
0 0 0
SY7 SY6 SY5
0 0 0
NX7 NX6 NX5
0 0 0
NY7 NY6 NY5
0 0 0
7 6 5
0 - -
Video or expansion RAM
(SX, SY)
NY
↓
4 3 2
SX4 SX3 SX2
0 0 0
SY4 SY3 SY2
0 0 0
NX4 NX3 NX2
0 0 0
NY4 NY3 NY2
0 0 0
4 3 2
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NX
DIY
1 0 LSB
SX1 SX0 SX: Source X
(0...511)
0 SX8
SY1 SY0 SY: Source Y
(0...1023)
SY9 SY8
NX1 NX0 NX: Number of
dots in X-axis
0 NX8
NY1 NY0 NY: Number of
NY9 NY8 dots in Y-axis
1 0 LSB
- -
0: Right X transfer
direction
1: Left
0: Down Y transfer
direction
1: Up
0: VRAM Source select
1: ExpRAM
© 2010-2015 Eugeny Brychkov
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