MAX1463 Datasheet, PDF (28/49 Pages) Maxim Integrated Products – Low-Power Two-Channel Sensor Signal Processor

Low-Power Two-Channel Sensor
Signal Processor
MLT Multiply
Op-code:
1111 0011_BINARY F3h
Operation:
A-register | M-register ← N-register x M-register
PC-register ← PC + 1 (point to next instruction)
CPU Cycles required:
16 cycles
Description:
Perform a 16-bit by 16-bit arithmetic multiplication of
the M-register and the N-register producing a 32-bit
result. The 32-bit result is stored in two 16-bit registers;
the A-register receives the most significant word of the
result and the M-register receives the least significant
word of the result.
The A-register must be cleared to zero (CLX A) before
executing the MLT instruction.
The previous contents of A-register are overwritten
and lost.
The previous contents of M-register are overwritten
and lost.
The contents of the N-register are not altered.
The register op code must be 3h.
PC is incremented once to point to the next instruction
in program memory.
Two’s complement data format is preserved.
No branching occurs.
No other registers are affected.
Table 1. CPU Registers
ADDRESS
0h
1h
2h
3h
4h
5h
6h–Fh
REF
R0
R1
R2
R3
R4
R5
R6–RF
ALT NAME
FUNCTION
P
Pointer Register. This register contains the address of the instruction or data in FLASH
memory to be fetched.
Accumulator Register. This register generally contains the result of any operation
A
involving two or more registers. It is the accumulator for the multiregister operation
result and can be used effectively to carry data from one computation to the next. The
A-register can read and write data to and from any other CPU port or register.
General-Purpose Register. This register is used to hold intermediate calculation
—
results, calculation coefficients, loop counter values, event counter values, comparison
limit values, etc.
Multiplicand Register. This register has a dedicated function when executing a
N
multiply (MLT) instruction, but can be used as a general-purpose register otherwise.
The contents of the N-register are not modified by the MLT instruction.
Multiplier Register. This register has a dedicated function when executing a multiply
(MLT) instruction, but can be used as a general-purpose register otherwise. The
M
contents of the M-register are modified by the MLT instruction. The data contents prior
to the execution of the MLT instruction are overwritten with the LSBs resulting product,
and hence lost.
Index Register. The branch not zero (BNX) and branch positive (BPX) instructions test
I
the index register, I, for conditions to determine if branching should occur. If the index
register tests true for the condition to branch, then the contents of register-X are added
to the pointer register, therefore executing a branch in the program.
—
General-Purpose Registers. Used to hold intermediate calculation results, calculation
coefficients, loop counter values, event counter values, comparison limit values, etc.
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