Shift ad Rotate with altmult_add

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Shift ad Rotate with altmult_add

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Hi,

To me it looks like Nios II does multiplication and shift/rotate with altmult_add on stratix iii, but when I look at the instantiation of the module in Nios II, it's not clear to me how it does shifting/rotation. Except two signals related to shift direction and shift/rotation mode, there's nothing there to request a shift/rotate operation rather than multiplication. Is there something I'm missing here? Any help is appreciated, thanks.

Here's how Nios II uses altmult_add.

altmult_add the_altmult_add

(

.aclr0 (mul_clr),

.aclr1 (mul_clr),

.clock0 (clk),

.clock1 (clk),

.dataa (E_src1_mul_cell),

.datab (E_src2_mul_cell),

.ena0 (M_en),

.ena1 (A_en),

.result (A_mul_cell_result),

.rotate (M_mul_cell_rotate),

.shift_right (M_mul_cell_shift_right),

.signa (E_ctrl_mul_shift_src1_signed),

.signb (E_ctrl_mul_shift_src2_signed)

);

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