diff options
Diffstat (limited to 'techlibs')
-rw-r--r-- | techlibs/common/techmap.v | 102 |
1 files changed, 35 insertions, 67 deletions
diff --git a/techlibs/common/techmap.v b/techlibs/common/techmap.v index 03c27d49d..2ab28e6e6 100644 --- a/techlibs/common/techmap.v +++ b/techlibs/common/techmap.v @@ -143,78 +143,46 @@ module _90_shift_shiftx (A, B, Y); localparam extbit = _TECHMAP_CELLTYPE_ == "$shift" ? 1'b0 : 1'bx; wire a_padding = _TECHMAP_CELLTYPE_ == "$shiftx" ? extbit : (A_SIGNED ? A[A_WIDTH-1] : 1'b0); - generate -`ifndef NO_LSB_FIRST_SHIFT_SHIFTX - // If $shift/$shiftx only shifts in units of Y_WIDTH - // (a common pattern created by pmux2shiftx) - // which is checked by ensuring that all that - // the appropriate LSBs of B are constant zero, - // then we can decompose LSB first instead of - // MSB first - localparam CLOG2_Y_WIDTH = $clog2(Y_WIDTH); - if (B_WIDTH > CLOG2_Y_WIDTH+1 && - _TECHMAP_CONSTMSK_B_[CLOG2_Y_WIDTH-1:0] == {CLOG2_Y_WIDTH{1'b1}} && - _TECHMAP_CONSTVAL_B_[CLOG2_Y_WIDTH-1:0] == {CLOG2_Y_WIDTH{1'b0}}) begin - // Halve the size of $shift/$shiftx by $mux-ing A according to - // the LSB of B, after discarding the zeroed bits - localparam Y_WIDTH2 = 2**CLOG2_Y_WIDTH; - localparam entries = (A_WIDTH+Y_WIDTH-1)/Y_WIDTH2; - localparam len = Y_WIDTH2 * ((entries+1)/2); - wire [len-1:0] AA; - wire [(A_WIDTH+Y_WIDTH2+Y_WIDTH-1)-1:0] Apad = {{(Y_WIDTH2+Y_WIDTH-1){a_padding}}, A}; - genvar i; - for (i = 0; i < A_WIDTH; i=i+Y_WIDTH2*2) - assign AA[i/2 +: Y_WIDTH2] = B[CLOG2_Y_WIDTH] ? Apad[i+Y_WIDTH2 +: Y_WIDTH2] : Apad[i +: Y_WIDTH2]; - wire [B_WIDTH-2:0] BB = {B[B_WIDTH-1:CLOG2_Y_WIDTH+1], {CLOG2_Y_WIDTH{1'b0}}}; - if (_TECHMAP_CELLTYPE_ == "$shift") - $shift #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(len), .B_WIDTH(B_WIDTH-1), .Y_WIDTH(Y_WIDTH)) _TECHMAP_REPLACE_ (.A(AA), .B(BB), .Y(Y)); - else - $shiftx #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(len), .B_WIDTH(B_WIDTH-1), .Y_WIDTH(Y_WIDTH)) _TECHMAP_REPLACE_ (.A(AA), .B(BB), .Y(Y)); - end - else -`endif - begin - localparam BB_WIDTH = `MIN($clog2(`MAX(A_WIDTH, Y_WIDTH)) + (B_SIGNED ? 2 : 1), B_WIDTH); - localparam WIDTH = `MAX(A_WIDTH, Y_WIDTH) + (B_SIGNED ? 2**(BB_WIDTH-1) : 0); + localparam BB_WIDTH = `MIN($clog2(`MAX(A_WIDTH, Y_WIDTH)) + (B_SIGNED ? 2 : 1), B_WIDTH); + localparam WIDTH = `MAX(A_WIDTH, Y_WIDTH) + (B_SIGNED ? 2**(BB_WIDTH-1) : 0); - wire [1023:0] _TECHMAP_DO_00_ = "proc;;"; - wire [1023:0] _TECHMAP_DO_01_ = "CONSTMAP; opt_muxtree; opt_expr -mux_undef -mux_bool -fine;;;"; + wire [1023:0] _TECHMAP_DO_00_ = "proc;;"; + wire [1023:0] _TECHMAP_DO_01_ = "CONSTMAP; opt_muxtree; opt_expr -mux_undef -mux_bool -fine;;;"; - integer i; - (* force_downto *) - reg [WIDTH-1:0] buffer; - reg overflow; + integer i; + (* force_downto *) + reg [WIDTH-1:0] buffer; + reg overflow; - always @* begin - overflow = 0; + always @* begin + overflow = 0; + buffer = {WIDTH{extbit}}; + buffer[Y_WIDTH-1:0] = {Y_WIDTH{a_padding}}; + buffer[A_WIDTH-1:0] = A; + + if (B_WIDTH > BB_WIDTH) begin + if (B_SIGNED) begin + for (i = BB_WIDTH; i < B_WIDTH; i = i+1) + if (B[i] != B[BB_WIDTH-1]) + overflow = 1; + end else + overflow = |B[B_WIDTH-1:BB_WIDTH]; + if (overflow) buffer = {WIDTH{extbit}}; - buffer[Y_WIDTH-1:0] = {Y_WIDTH{a_padding}}; - buffer[A_WIDTH-1:0] = A; - - if (B_WIDTH > BB_WIDTH) begin - if (B_SIGNED) begin - for (i = BB_WIDTH; i < B_WIDTH; i = i+1) - if (B[i] != B[BB_WIDTH-1]) - overflow = 1; - end else - overflow = |B[B_WIDTH-1:BB_WIDTH]; - if (overflow) - buffer = {WIDTH{extbit}}; - end - - for (i = BB_WIDTH-1; i >= 0; i = i-1) - if (B[i]) begin - if (B_SIGNED && i == BB_WIDTH-1) - buffer = {buffer, {2**i{extbit}}}; - else if (2**i < WIDTH) - buffer = {{2**i{extbit}}, buffer[WIDTH-1 : 2**i]}; - else - buffer = {WIDTH{extbit}}; - end - end - assign Y = buffer; end - endgenerate + + if (B_SIGNED && B[BB_WIDTH-1]) + buffer = {buffer, {2**(BB_WIDTH-1){extbit}}}; + + for (i = 0; i < (B_SIGNED ? BB_WIDTH-1 : BB_WIDTH); i = i+1) + if (B[i]) begin + if (2**i < WIDTH) + buffer = {{2**i{extbit}}, buffer[WIDTH-1 : 2**i]}; + else + buffer = {WIDTH{extbit}}; + end + end + assign Y = buffer; endmodule |