
MOTOROLA
MC68HC916X1
52
MC68HC916X1TS/D
4.3 Programming Model
Figure 11 CPU16 Programming Model
20
16 15
8 7
0 BIT POSITION
A
B
ACCUMULATORS A AND B
D
ACCUMULATOR D (A : B)
E
ACCUMULATOR E
XK
IX
INDEX REGISTER X
YK
IY
INDEX REGISTER Y
ZK
IZ
INDEX REGISTER Z
SK
SP
STACK POINTER
PK
PC
PROGRAM COUNTER
CCR
PK
CONDITION CODE REGISTER
PC EXTENSION REGISTER
EK
XK
YK
ZK
ADDRESS EXTENSION REGISTER
SK
STACK EXTENSION REGISTER
HR
MAC MULTIPLIER REGISTER
IR
MAC MULTIPLICAND REGISTER
35
16
AM (MSB)
MAC ACCUMULATORMSB [35:16]
AM (LSB)
MAC ACCUMULATOR LSB [15:0]
XMSK
YMSK
MAC XY MASK REGISTER
Accumulator A — 8-bit general-purpose register
Accumulator B — 8-bit general-purpose register
Accumulator D — 16-bit general-purpose register formed by concatenating accumulators A and B
Accumulator E — 16-bit general-purpose register
Index Register X — 16-bit indexing register, addressing extended by XK field in K register
Index Register Y — 16-bit indexing register, addressing extended by YK field in K register
Index Register Z — 16-bit indexing register, addressing extended by ZK field in K register
Stack Pointer — 16-bit dedicated register, addressing extended by the SK register
Program Counter — 16-bit dedicated register, addressing extended by PK field in CCR
Condition Code Register — 16-bit register containing condition flags, interrupt priority mask, and the program
counter address extension field
K Register — 16-bit register made up of four 4-bit address extension fields
SK Register — 4-bit register containing the stack pointer address extension field
H Register — 16-bit multiply and accumulate input (multiplier) register
I Register — 16-bit multiply and accumulate input (multiplicand) register
MAC Accumulator — 36-bit multiply and accumulate result register
XMSK, YMSK — Determine which bits change when an offset is added
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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