diff options
-rw-r--r-- | techlibs/common/Makefile.inc | 1 | ||||
-rw-r--r-- | techlibs/common/shiftx2mux.v | 38 | ||||
-rw-r--r-- | techlibs/common/techmap.v | 103 | ||||
-rw-r--r-- | tests/techmap/shiftx2mux.ys | 8 |
4 files changed, 73 insertions, 77 deletions
diff --git a/techlibs/common/Makefile.inc b/techlibs/common/Makefile.inc index 5d797ec1d..a42f63128 100644 --- a/techlibs/common/Makefile.inc +++ b/techlibs/common/Makefile.inc @@ -30,4 +30,3 @@ $(eval $(call add_share_file,share,techlibs/common/cmp2lut.v)) $(eval $(call add_share_file,share,techlibs/common/cells.lib)) $(eval $(call add_share_file,share,techlibs/common/mul2dsp.v)) $(eval $(call add_share_file,share,techlibs/common/dummy.box)) -$(eval $(call add_share_file,share,techlibs/common/shiftx2mux.v)) diff --git a/techlibs/common/shiftx2mux.v b/techlibs/common/shiftx2mux.v deleted file mode 100644 index 5366d6749..000000000 --- a/techlibs/common/shiftx2mux.v +++ /dev/null @@ -1,38 +0,0 @@ -(* techmap_celltype = /*"$shift*/ "$shiftx" *) -module _80_shift_shiftx (A, B, Y); - parameter A_SIGNED = 0; - parameter B_SIGNED = 0; - parameter A_WIDTH = 1; - parameter B_WIDTH = 1; - parameter Y_WIDTH = 1; - - input [A_WIDTH-1:0] A; - input [B_WIDTH-1:0] B; - output [Y_WIDTH-1:0] Y; - - parameter [B_WIDTH-1:0] _TECHMAP_CONSTMSK_B_ = 0; - parameter [B_WIDTH-1:0] _TECHMAP_CONSTVAL_B_ = 0; - - generate - genvar i; - localparam CLOG2_Y_WIDTH = $clog2(Y_WIDTH); - - if (B_WIDTH <= CLOG2_Y_WIDTH+1) - wire _TECHMAP_FAIL_ = 1; - // In order to perform this optimisation, this $shiftx must - // only shift in units of Y_WIDTH, which we check by ensuring - // that the appropriate LSBs of B are zero - else if (_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}}) - wire _TECHMAP_FAIL_ = 1; - else begin - // Halve the size of $shiftx by $mux-ing A according to - // the LSB of B, after discarding the zeroed bits - wire [(A_WIDTH+Y_WIDTH)/2-1:0] AA; - for (i = 0; i < (A_WIDTH/Y_WIDTH); i=i+2) - assign AA[(i/2)*Y_WIDTH +: Y_WIDTH] = B[CLOG2_Y_WIDTH] ? A[(i+1)*Y_WIDTH +: Y_WIDTH] : A[(i+0)*Y_WIDTH +: Y_WIDTH]; - $shiftx #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH((A_WIDTH+Y_WIDTH)/2'd2), .B_WIDTH(B_WIDTH-1), .Y_WIDTH(Y_WIDTH)) _TECHMAP_REPLACE_ (.A(AA), .B({B[B_WIDTH-1:CLOG2_Y_WIDTH+1], {CLOG2_Y_WIDTH{1'b0}}}), .Y(Y)); - end - endgenerate -endmodule - - diff --git a/techlibs/common/techmap.v b/techlibs/common/techmap.v index d7ec3947e..83bd4333c 100644 --- a/techlibs/common/techmap.v +++ b/techlibs/common/techmap.v @@ -129,47 +129,82 @@ module _90_shift_shiftx (A, B, Y); input [B_WIDTH-1:0] B; output [Y_WIDTH-1:0] Y; - localparam BB_WIDTH = `MIN($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); - parameter _TECHMAP_CELLTYPE_ = ""; + parameter [B_WIDTH-1:0] _TECHMAP_CONSTMSK_B_ = 0; + parameter [B_WIDTH-1:0] _TECHMAP_CONSTVAL_B_ = 0; + localparam extbit = _TECHMAP_CELLTYPE_ == "$shift" ? 1'b0 : 1'bx; - wire [1023:0] _TECHMAP_DO_00_ = "proc;;"; - wire [1023:0] _TECHMAP_DO_01_ = "CONSTMAP; opt_muxtree; opt_expr -mux_undef -mux_bool -fine;;;"; + 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 $mux-ing A according to + // the LSB of B, after discarding the zeroed bits + localparam len = 2**(B_WIDTH-1); + wire [len-1:0] T, F; + genvar i; + for (i = 0; i < A_WIDTH; i=i+Y_WIDTH*2) begin + assign F[i/2 +: Y_WIDTH] = A[i +: Y_WIDTH]; + assign T[i/2 +: Y_WIDTH] = (i + Y_WIDTH < A_WIDTH) ? A[i+Y_WIDTH +: Y_WIDTH] : {Y_WIDTH{extbit}}; + end + wire [len-1:0] AA = B[CLOG2_Y_WIDTH] ? T : F; + wire [B_WIDTH-2:0] BB = {B[B_WIDTH-1:CLOG2_Y_WIDTH+1], {CLOG2_Y_WIDTH{1'b0}}}; + if (_TECHMAP_CELLTYPE_ == "$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); - integer i; - reg [WIDTH-1:0] buffer; - reg overflow; + wire [1023:0] _TECHMAP_DO_00_ = "proc;;"; + wire [1023:0] _TECHMAP_DO_01_ = "CONSTMAP; opt_muxtree; opt_expr -mux_undef -mux_bool -fine;;;"; - always @* begin - overflow = 0; - buffer = {WIDTH{extbit}}; - buffer[`MAX(A_WIDTH, Y_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 + integer i; + reg [WIDTH-1:0] buffer; + reg overflow; - 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}}; + always @* begin + overflow = 0; + buffer = {WIDTH{extbit}}; + buffer[`MAX(A_WIDTH, Y_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 - end - - assign Y = buffer; + assign Y = buffer; + end + endgenerate endmodule diff --git a/tests/techmap/shiftx2mux.ys b/tests/techmap/shiftx2mux.ys index acdd54e9e..c13b5f600 100644 --- a/tests/techmap/shiftx2mux.ys +++ b/tests/techmap/shiftx2mux.ys @@ -74,13 +74,13 @@ design -save gold design -load gold -techmap +techmap -D NO_LSB_FIRST_SHIFT_SHIFTX abc -lut 6 select -assert-min 17 t:$lut design -load gold -techmap -map +/shiftx2mux.v -map +/techmap.v +techmap abc -lut 6 select -assert-count 16 t:$lut @@ -92,13 +92,13 @@ sat -verify -prove-asserts -show-ports miter design -load gold -techmap +techmap -D NO_LSB_FIRST_SHIFT_SHIFTX abc9 -lut 6 select -assert-min 17 t:$lut design -load gold -techmap -map +/shiftx2mux.v -map +/techmap.v +techmap abc9 -lut 6 select -assert-count 16 t:$lut |