D950-Core
4.2.2 Registers
The D950-Core ACU includes two types of registers: data registers and control registers
Data registers:
The following registers are directly addressed by instructions:
• 2 x 16-bit pointer registers and 4 x 16-bit index registers are dedicated for each
data memory space:
• AX0/AX1 (pointer), IX0/IX1/IX2/IX3 (index) for X-memory space,
• AY0/AY1 (pointer), IY0/IY1/IY2/IY3 (index) for Y-memory space.
In addition to these registers, 16-bit SP registers address the stacks located in the X and Y-
memory spaces.
The following four registers are mapped in Y-memory space:
• 2 x 16-bit base and maximum address registers are dedicated for each Data
memory space:
• BX (Base), MX (Maximum) for X-memory space,
• BY (Base), MY (Maximum) for Y-memory space.
Control Register:
STA: Bits 8 to 13 are dedicated to ACU (see Section 4.5.1). Index register values are 16-bit
signed.
4.2.3 Addressing modes
The D950-Core provides the following addressing modes:.
Addressing Modes
DIRECT
INDIRECT
IMMEDIATE
STACK
Type
LINEAR POST- INCREMENT
MODULO POST-INCREMENT
BIT-REVERSE POST-INCREMENT
INDEXED
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