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EP1S30F780C6 Datasheet, PDF (84/864 Pages) Altera Corporation – Stratix Device Handbook, Volume 1 | |||
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Digital Signal Processing Block
Table 2â14 shows the summary of input register modes for the DSP block.
Table 2â14. Input Register Modes
Register Input Mode
Parallel input
Shift register input
9Ã9
v
v
18 Ã 18
v
v
36 Ã 36
v
Multiplier
The multiplier supports 9 Ã 9-, 18 Ã 18-, or 36 Ã 36-bit multiplication. Each
DSP block supports eight possible 9 Ã 9-bit or smaller multipliers. There
are four multiplier blocks available for multipliers larger than 9 Ã 9 bits
but smaller than 18 Ã 18 bits. There is one multiplier block available for
multipliers larger than 18 Ã 18 bits but smaller than or equal to 36 Ã 36
bits. The ability to have several small multipliers is useful in applications
such as video processing. Large multipliers greater than 18 Ã 18 bits are
useful for applications such as the mantissa multiplication of a single-
precision floating-point number.
The multiplier operands can be signed or unsigned numbers, where the
result is signed if either input is signed as shown in Table 2â15. The
sign_a and sign_b signals provide dynamic control of each operandâs
representation: a logic 1 indicates the operand is a signed number, a logic
0 indicates the operand is an unsigned number. These sign signals affect
all multipliers and adders within a single DSP block and you can register
them to match the data path pipeline. The multipliers are full precision
(that is, 18 bits for the 18-bit multiply, 36-bits for the 36-bit multiply, and
so on) regardless of whether sign_a or sign_b set the operands as
signed or unsigned numbers.
Table 2â15. Multiplier Signed Representation
Data A
Unsigned
Unsigned
Signed
Signed
Data B
Unsigned
Signed
Unsigned
Signed
Result
Unsigned
Signed
Signed
Signed
2â60
Stratix Device Handbook, Volume 1
Altera Corporation
July 2005
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