diff options
Diffstat (limited to 'techlibs/ice40/cells_box.v')
| -rw-r--r-- | techlibs/ice40/cells_box.v | 24 |
1 files changed, 15 insertions, 9 deletions
diff --git a/techlibs/ice40/cells_box.v b/techlibs/ice40/cells_box.v index e2a54a42c..d0eb8708c 100644 --- a/techlibs/ice40/cells_box.v +++ b/techlibs/ice40/cells_box.v @@ -1,12 +1,18 @@ (* abc_box_id = 1 *) -module SB_CARRY (output CO, input CI, I0, I1); - assign CO = (I0 && I1) || ((I0 || I1) && CI); -endmodule +module ICE40_CARRY_LUT (output CO, O, input CI, I1, I2); + assign CO = (I1 && I2) || ((I1 || I2) && CI); -(* abc_box_id = 2 *) -module SB_LUT4 (output O, input I0, I1, I2, I3); - parameter [15:0] LUT_INIT = 0; - // Indicate this is a black-box - assign O = 1'b0; -endmodule + wire I0, I3; + assign I0 = 1'b0; + assign I3 = CI; + // I0: 1010 1010 1010 1010 + // I1: 1100 1100 1100 1100 + // I2: 1111 0000 1111 0000 + // I3: 1111 1111 0000 0000 + localparam [15:0] LUT_INIT = 16'b 0110_1001_1001_0110; + wire [7:0] s3 = I3 ? LUT_INIT[15:8] : LUT_INIT[7:0]; + wire [3:0] s2 = I2 ? s3[ 7:4] : s3[3:0]; + wire [1:0] s1 = I1 ? s2[ 3:2] : s2[1:0]; + assign O = I0 ? s1[1] : s1[0]; +endmodule |