tex_unit code refactoring

hw/rtl/tex_unit/VX_tex_bilerp.v

@@ -0,0 +1,67 @@
+`include "VX_tex_define.vh"
+
+module VX_tex_bilerp #(
+    parameter CORE_ID = 0
+) (
+    input wire [`BLEND_FRAC_64-1:0]   blendU,
+    input wire [`BLEND_FRAC_64-1:0]   blendV,
+
+    input wire [3:0][63:0]            texels,
+    input wire [`TEX_FORMAT_BITS-1:0] color_enable,
+
+    output wire [31:0]                sampled_data
+);  
+    `UNUSED_PARAM (CORE_ID)
+    `UNUSED_VAR(color_enable)
+
+    wire [63:0] UL_lerp;
+    wire [63:0] UH_lerp;
+    wire [63:0] V_lerp;
+    reg [31:0] sampled_r;
+
+    VX_lerp_64 #(
+    ) UL_lerp (
+        .blend(blendU), 
+        .in_texels({texels[1], texels[0]}),
+        .lerp_texel(UL_lerp)
+    );  
+
+    VX_lerp_64 #(
+    ) UH_lerp (
+        .blend(blendU), 
+        .in_texels({texels[3], texels[2]}),
+        .lerp_texel(UH_lerp)
+    );  
+
+    VX_lerp_64 #(
+    ) V_lerp (
+        .blend(blendV), 
+        .in_texels({UH_lerp, UL_lerp}),
+        .lerp_texel(V_lerp)
+    );  
+
+    always @(*) begin
+        if (color_enable[3]==1) //R
+            sampled_r[31:24] = V_lerp[55:48];
+        else
+            sampled_r[31:24] = {`TEX_COLOR_BITS{1'b0}};
+
+        if (color_enable[2]==1) //G
+            sampled_r[23:16] = V_lerp[39:32];
+        else
+            sampled_r[23:16] = {`TEX_COLOR_BITS{1'b0}};
+
+        if (color_enable[1]==1) //B
+            sampled_r[15:8] = V_lerp[23:16];
+        else
+            sampled_r[15:8] = {`TEX_COLOR_BITS{1'b0}};
+
+        if (color_enable[0]==1) //A
+            sampled_r[7:0] = V_lerp[7:0];
+        else
+            sampled_r[7:0] = {`TEX_COLOR_BITS{1'b1}};
+    end
+
+    assign sampled_data = sampled_r;
+
+endmodule

hw/rtl/tex_unit/VX_tex_lerp.v

@@ -0,0 +1,18 @@
+`include "VX_tex_define.vh"
+
+module VX_tex_lerp #(
+) (
+    input wire [`BLEND_FRAC_64-1:0]   blend, 
+    input wire [1:0][63:0]            in_texels,
+
+    output wire [63:0]                lerp_texel
+);  
+
+    wire [63:0] lerp_i1;
+    wire [63:0] lerp_i2; // >> BLEND_FRAC_64 / >> 8
+
+    assign lerp_i1 = (in_texels[0] - in_texels[1]) * blend;
+    assign lerp_i2 = in_texels[1] + {8'h00,lerp_i1[63:56], 8'h00,lerp_i1[47:40], 8'h00,lerp_i1[31:24], 8'h00,lerp_i1[15:8]};
+    assign lerp_texel = lerp_i2 & 64'h00ff00ff00ff00ff;
+
+endmodule