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Do not load next word when loading a 16 bit opcode from the upper half of a 32bit word

This commit is contained in:
Clifford Wolf 2016-04-11 14:32:25 +02:00
parent 99cff42b48
commit b08d9400bd
1 changed files with 7 additions and 4 deletions
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picorv32.v
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@ -218,17 +218,20 @@ module picorv32 #(
reg [15:0] mem_16bit_buffer; reg [15:0] mem_16bit_buffer;
wire mem_busy = |{mem_do_prefetch, mem_do_rinst, mem_do_rdata, mem_do_wdata}; wire mem_busy = |{mem_do_prefetch, mem_do_rinst, mem_do_rdata, mem_do_wdata};
wire mem_done = resetn && ((mem_valid && mem_ready && |mem_state && (mem_do_rinst || mem_do_rdata || mem_do_wdata)) || (&mem_state && mem_do_rinst)) && !mem_la_firstword; wire mem_done = resetn && ((mem_valid && mem_ready && |mem_state && (mem_do_rinst || mem_do_rdata || mem_do_wdata)) || (&mem_state && mem_do_rinst)) &&
(!mem_la_firstword || (~&mem_rdata[17:16] && mem_valid && mem_ready));
assign mem_la_write = resetn && !mem_state && mem_do_wdata; assign mem_la_write = resetn && !mem_state && mem_do_wdata;
assign mem_la_read = resetn && ((!mem_state && (mem_do_rinst || mem_do_prefetch || mem_do_rdata)) || (mem_valid && mem_ready && mem_la_firstword && !mem_la_secondword)); assign mem_la_read = resetn && ((!mem_state && (mem_do_rinst || mem_do_prefetch || mem_do_rdata)) ||
(COMPRESSED_ISA && mem_valid && mem_ready && mem_la_firstword && !mem_la_secondword && &mem_rdata[17:16]));
assign mem_la_addr = (mem_do_prefetch || mem_do_rinst) ? {next_pc[31:2] + (mem_valid && mem_ready && mem_la_firstword), 2'b00} : {reg_op1[31:2], 2'b00}; assign mem_la_addr = (mem_do_prefetch || mem_do_rinst) ? {next_pc[31:2] + (mem_valid && mem_ready && mem_la_firstword), 2'b00} : {reg_op1[31:2], 2'b00};
wire [31:0] mem_rdata_latched_noshuffle; wire [31:0] mem_rdata_latched_noshuffle;
assign mem_rdata_latched_noshuffle = ((mem_valid && mem_ready) || LATCHED_MEM_RDATA) ? mem_rdata : mem_rdata_q; assign mem_rdata_latched_noshuffle = ((mem_valid && mem_ready) || LATCHED_MEM_RDATA) ? mem_rdata : mem_rdata_q;
wire [31:0] mem_rdata_latched; wire [31:0] mem_rdata_latched;
assign mem_rdata_latched = COMPRESSED_ISA && mem_la_secondword ? {mem_rdata_latched_noshuffle[15:0], mem_16bit_buffer} : mem_rdata_latched_noshuffle; assign mem_rdata_latched = COMPRESSED_ISA && mem_la_secondword ? {mem_rdata_latched_noshuffle[15:0], mem_16bit_buffer} :
COMPRESSED_ISA && mem_la_firstword ? {16'bx, mem_rdata_latched_noshuffle[31:16]} : mem_rdata_latched_noshuffle;
always @* begin always @* begin
(* full_case *) (* full_case *)
@ -401,7 +404,7 @@ module picorv32 #(
end end
1: begin 1: begin
if (mem_ready) begin if (mem_ready) begin
if (COMPRESSED_ISA && mem_la_firstword && !mem_la_secondword) begin if (COMPRESSED_ISA && mem_la_read) begin
mem_addr <= mem_la_addr; mem_addr <= mem_la_addr;
mem_la_secondword <= 1; mem_la_secondword <= 1;
mem_16bit_buffer <= mem_rdata[31:16]; mem_16bit_buffer <= mem_rdata[31:16];