| Line 52... |
Line 52... |
);
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);
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//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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//
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//
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//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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reg [4:0] keys [0:7]; // 8 rows of 5 bits each
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reg [4:0] keys [0:7]; // 8 rows of 5 bits each: contains 0 for a pressed key at a specific location, 1 otherwise
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reg released; // Tracks "released" scan code (F0)
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reg released; // Tracks "released" scan code (F0): contains 0 when a key is pressed, 1 otherwise
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reg extended; // Tracks "extended" scan code (E0)
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reg extended; // Tracks "extended" scan code (E0)
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reg shifted; // Tracks local "shifted" state
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reg shifted; // Tracks local "shifted" state
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// Calculate a "key is pressed" signal
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// Calculate a "key is pressed" signal
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assign pressed = ~(&keys[7] & &keys[6] & &keys[5] & &keys[4] & &keys[3] & &keys[2] & &keys[1] & &keys[0]);
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assign pressed = ~(&keys[7] & &keys[6] & &keys[5] & &keys[4] & &keys[3] & &keys[2] & &keys[1] & &keys[0]);
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| Line 89... |
Line 89... |
keys[5] <= '1;
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keys[5] <= '1;
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keys[6] <= '1;
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keys[6] <= '1;
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keys[7] <= '1;
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keys[7] <= '1;
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end else
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end else
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if (scan_code_ready) begin
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if (scan_code_ready) begin
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if (scan_code==8'hE0)
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if (scan_code==8'hE0) // Extended code prefix byte
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extended <= 1;
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extended <= 1;
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else if (scan_code==8'hF0)
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else if (scan_code==8'hF0) // Break code prefix byte
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released <= 1;
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released <= 1;
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else begin
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else begin
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// Cancel release/extended flags for the next clock
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// Cancel release/extended flags for the next clock
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extended <= 0;
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extended <= 0;
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released <= 0;
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released <= 0;
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| Line 121... |
Line 121... |
end
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end
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endcase
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endcase
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end
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end
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else begin
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else begin
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// For each PS/2 scan-code, set the ZX keyboard matrix state
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// For each PS/2 scan-code, set the ZX keyboard matrix state
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// 'released' contains 0 when a key is pressed; 1 otherwise
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case (scan_code)
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case (scan_code)
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8'h12: shifted <= !released; // Local SHIFT key (left)
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8'h12: shifted <= !released; // Local SHIFT key (left)
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8'h59: shifted <= !released; // Local SHIFT key (right)
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8'h59: shifted <= !released; // Local SHIFT key (right)
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8'h14: keys[0][0] <= released; // CAPS SHIFT = Left or right Ctrl
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8'h14: keys[0][0] <= released; // CAPS SHIFT = Left or right Ctrl
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| Line 183... |
Line 182... |
end
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end
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8'h76: begin // ESC -> BREAK
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8'h76: begin // ESC -> BREAK
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keys[0][0] <= released; // CAPS SHIFT
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keys[0][0] <= released; // CAPS SHIFT
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keys[7][0] <= released; // SPACE
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keys[7][0] <= released; // SPACE
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end
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end
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// With shifted keys, we need to make inactive (set to 1) other corresponding key
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// Otherwise, it will stay active if the shift was released first
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8'h4E: begin // - or (shifted) _
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8'h4E: begin // - or (shifted) _
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if (!shifted) begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[6][3] <= released; // J
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keys[4][0] <= shifted ? released : 1; // 0
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end
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keys[6][3] <= shifted ? 1 : released; // J
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else begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[4][0] <= released; // 0
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end
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end
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end
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8'h55: begin // = or (shifted) +
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8'h55: begin // = or (shifted) +
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if (!shifted) begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[6][1] <= released; // L
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keys[6][2] <= shifted ? released : 1; // K
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end
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keys[6][1] <= shifted ? 1 : released; // L
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else begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[6][2] <= released; // K
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end
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end
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end
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8'h52: begin // ' or (shifted) "
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8'h52: begin // ' or (shifted) "
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if (!shifted) begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[4][3] <= released; // 7
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keys[5][0] <= shifted ? released : 1; // P
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end
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keys[4][3] <= shifted ? 1 : released; // 7
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else begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[5][0] <= released; // P
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end
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end
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end
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8'h4C: begin // ; or (shifted) :
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8'h4C: begin // ; or (shifted) :
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if (!shifted) begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[5][1] <= released; // O
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keys[0][1] <= shifted ? released : 1; // Z
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end
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keys[5][1] <= shifted ? 1 : released; // O
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else begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[0][1] <= released; // Z
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end
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end
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end
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8'h41: begin // , or (shifted) <
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8'h41: begin // , or (shifted) <
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if (!shifted) begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][3] <= released; // N
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keys[2][3] <= shifted ? released : 1; // R
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end
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keys[7][3] <= shifted ? 1 : released; // N
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else begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[2][3] <= released; // R
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end
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end
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end
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8'h49: begin // . or (shifted) >
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8'h49: begin // . or (shifted) >
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if (!shifted) begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][2] <= released; // M
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end
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else begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[2][4] <= released; // T
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keys[2][4] <= shifted ? released : 1; // T
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end
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keys[7][2] <= shifted ? 1 : released; // M
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end
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end
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8'h4A: begin // / or (shifted) ?
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8'h4A: begin // / or (shifted) ?
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if (!shifted) begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[0][4] <= released; // V
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keys[0][3] <= shifted ? released : 1; // C
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end
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keys[0][4] <= shifted ? 1 : released; // V
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else begin
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keys[7][1] <= released; // SYMBOL SHIFT (Red)
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keys[0][3] <= released; // C
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end
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end
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end
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endcase
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endcase
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end
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end
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end
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end
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end
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end
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