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Update LIFOstack to support 32 memory slots

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Also fixed typo on line 15, previous version had a pointer for 16 slots but the memory register only had 4 slots
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Aadi Desai 2020-06-07 20:05:46 +01:00 committed by GitHub
parent 42739283f5
commit 94124c5a0e
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GPG key ID: 4AEE18F83AFDEB23
1 changed files with 6 additions and 6 deletions
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12
LIFOstack.v
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@ -10,18 +10,18 @@ output reg [15:0] Dout; // Data being pulled from stack
output reg empty; // goes high to indicate SP is at 0 output reg empty; // goes high to indicate SP is at 0
output reg full; // goes high to indicate SP is at (slots) output reg full; // goes high to indicate SP is at (slots)
reg [4:0] SP; // Points to slot to save next value to reg [5:0] SP; // Points to slot to save next value to
integer i; integer i;
reg [15:0] mem [3:0]; reg [15:0] mem [31:0];
always @ (posedge clk) begin always @ (posedge clk) begin
if (!en); // if not enabled, ignore this cycle if (!en); // if not enabled, ignore this cycle
else begin else begin
if (rst) begin // if rst is high, clear memory and reset pointers/outputs if (rst) begin // if rst is high, clear memory and reset pointers/outputs
Dout = 16'h0000; Dout = 16'h0000;
SP = 4'b0000; SP = 6'b000000;
empty = 1'b1; empty = 1'b1;
for (i = 0; i < 16; i = i + 1) begin for (i = 0; i < 32; i = i + 1) begin
mem[i] = 16'h0000; mem[i] = 16'h0000;
end end
end end
@ -29,7 +29,7 @@ always @ (posedge clk) begin
if (!full && rw) begin // Write when NOT full & Writing if (!full && rw) begin // Write when NOT full & Writing
mem[SP] = Din; // Store data into current slot mem[SP] = Din; // Store data into current slot
SP = SP + 1'b1; // Increment stack pointer to next empty slot SP = SP + 1'b1; // Increment stack pointer to next empty slot
full = (SP == 5'b10000) ? 1 : 0; // Stack is full if SP is (slots) full = (SP == 6'b100000) ? 1 : 0; // Stack is full if SP is (slots)
empty = 1'b0; // Stack is never empty after a push empty = 1'b0; // Stack is never empty after a push
end end
else if (!empty && !rw) begin // Read when NOT empty & reading else if (!empty && !rw) begin // Read when NOT empty & reading
@ -37,7 +37,7 @@ always @ (posedge clk) begin
Dout = mem[SP]; // Output data from last filled slot Dout = mem[SP]; // Output data from last filled slot
mem[SP] = 16'h0000; // Clear slot after setting output mem[SP] = 16'h0000; // Clear slot after setting output
full = 1'b0; // Stack is never full after a pop full = 1'b0; // Stack is never full after a pop
empty = (SP == 5'b00000) ? 1 : 0; // Stack is empty if SP is 0 empty = (SP == 6'b000000) ? 1 : 0; // Stack is empty if SP is 0
end end
end end
end end