ice40/cells_sim.v: LSB of A/B only signed in 8x8 mode

Signed-off-by: David Shah <dave@ds0.me>

diff --git a/techlibs/ice40/cells_sim.v b/techlibs/ice40/cells_sim.v
index 609facc9319bc28162b0f92977960aecbed3535d..4402f8d36ce4ebb92be60faa555cae8f0f734536 100644 (file)
--- a/techlibs/ice40/cells_sim.v
+++ b/techlibs/ice40/cells_sim.v
@@ -1363,9 +1363,9 @@ module SB_MAC16 (
        wire [15:0] p_Ah_Bh, p_Al_Bh, p_Ah_Bl, p_Al_Bl;
        wire [15:0] Ah, Al, Bh, Bl;
        assign Ah = {A_SIGNED ? {8{iA[15]}} : 8'b0, iA[15: 8]};
-       assign Al = {A_SIGNED ? {8{iA[ 7]}} : 8'b0, iA[ 7: 0]};
+       assign Al = {A_SIGNED && MODE_8x8 ? {8{iA[ 7]}} : 8'b0, iA[ 7: 0]};
        assign Bh = {B_SIGNED ? {8{iB[15]}} : 8'b0, iB[15: 8]};
-       assign Bl = {B_SIGNED ? {8{iB[ 7]}} : 8'b0, iB[ 7: 0]};
+       assign Bl = {B_SIGNED && MODE_8x8 ? {8{iB[ 7]}} : 8'b0, iB[ 7: 0]};
        assign p_Ah_Bh = Ah * Bh;
        assign p_Al_Bh = Al * Bh;
        assign p_Ah_Bl = Ah * Bl;