Analog Devices adsp-2100

Computational Units
2 – 11
2
divisor MSB and the ALU output MSB, and the quotient bit is this value
inverted. The quotient bit is loaded into the LSB of the AY0 register which is
also shifted left by one bit. The DIVQ operation is illustrated in Figure 2.4.
MUX
AX1
AX0
R-BUS
DIVISOR
MSB
AQ
X
Y
ALU
1 MSB
L
S
B
AF
AY0
LOWER
DIVIDEND
LEFT SHIFT
15
PARTIAL
REMAINDER
16
R=Y+X IF AQ=1
R=Y-X IF AQ=0
15 LSBs
Figure 2.4 DIVQ Operation
The format of the quotient for any numeric representation can be
determined by the format of the dividend and divisor. Let NL represent
the number of bits to the left of the binary point, and NR represent the
number of bits to the right of the binary point of the dividend; DL
represent the number of bits to the left of the binary point, and DR
represent the number of bits to the right of the binary point of the divisor;
then the quotient has NL–DL+1 bits to the left of the binary point and NR–
DR–1 bits to the right of the binary point.