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start implementing block Axx

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Raphaël Jacquot 2019-03-05 06:26:33 +01:00
parent f3d1a4d9d4
commit ddae7f9332
1 changed files with 32 additions and 0 deletions
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32
saturn_inst_decoder.v
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@ -135,9 +135,12 @@ reg [0:0] block_80x;
reg [0:0] block_80Cx;
reg [0:0] block_82x;
reg [0:0] block_84x_85x;
reg [0:0] block_Ax;
reg [0:0] block_Axx;
reg [0:0] block_JUMP;
reg [0:0] block_LOAD;
reg [0:0] block_FIELDS;
/*
* temporary variables
@ -180,9 +183,12 @@ initial begin
block_80Cx = 1'b0;
block_82x = 1'b0;
block_84x_85x = 1'b0;
block_Ax = 1'b0;
block_Axx = 1'b0;
block_JUMP = 1'b0;
block_LOAD = 1'b0;
block_FIELDS = 1'b0;
/* local variables */
jump_counter = 3'd0;
@ -240,6 +246,11 @@ always @(posedge i_clk) begin
block_JUMP <= 1'b1;
end
4'h8: block_8x <= 1'b1;
4'hA:
begin
block_Ax <= 1'b1;
block_FIELDS <= 1'b1;
end
default:
begin
$display("invalid instruction");
@ -433,6 +444,19 @@ always @(posedge i_clk) begin
block_84x_85x <= 1'b0;
end
if (block_Ax) begin
$display("DECODER %0d: [%d] block_Ax %h", i_phase, i_cycle_ctr, i_nibble);
/* work here is done by the block_FIELDS */
block_Axx <= 1'b1;
block_Ax <= 1'b0;
end
if (block_Axx) begin
$display("DECODER %0d: [%d] block_Axx %h", i_phase, i_cycle_ctr, i_nibble);
o_decoder_error <= 1'b1;
block_Axx <= 1'b0;
end
/* special cases */
if (block_JUMP) begin
@ -455,6 +479,11 @@ always @(posedge i_clk) begin
end
end
if (block_FIELDS) begin
$display("DECODER %0d: [%d] block_FIELDS %h", i_phase, i_cycle_ctr, i_nibble);
block_FIELDS <= 1'b0;
end
end
/* need to increment this at the same time the pointer is used */
@ -507,9 +536,12 @@ always @(posedge i_clk) begin
block_80Cx <= 1'b0;
block_82x <= 1'b0;
block_84x_85x <= 1'b0;
block_Ax <= 1'b0;
block_Axx <= 1'b0;
block_JUMP <= 1'b0;
block_LOAD <= 1'b0;
block_FIELDS <= 1'b0;
/* local variables */
jump_counter <= 3'd0;