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Further cleanups, try to make the code a bit easier to understand...

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This commit is contained in:
Andreas Traber 2015-09-23 15:57:57 +02:00
parent d988f06f0e
commit b41b2a697d
1 changed files with 24 additions and 61 deletions
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85
prefetch_L0_buffer.sv
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@ -110,15 +110,16 @@ module prefetch_L0_buffer
clear_buffer = 1'b0;
case(addr_o[3:2])
2'b00: begin unaligned_rdata_o = {L0_buffer[0][15:0], previous_chunk }; unaligned_valid_o = valid_previous_chunk; end
2'b01: begin unaligned_rdata_o = {L0_buffer[1][15:0], L0_buffer[0][31:16] }; unaligned_valid_o = valid_o; end
2'b10: begin unaligned_rdata_o = {L0_buffer[2][15:0], L0_buffer[1][31:16] }; unaligned_valid_o = valid_o; end
2'b11: begin unaligned_rdata_o = {L0_buffer[3][15:0], L0_buffer[2][31:16] }; unaligned_valid_o = valid_o; end
2'b00: begin unaligned_rdata_o = {L0_buffer[0][15:0], previous_chunk }; unaligned_valid_o = valid_previous_chunk; end
2'b01: begin unaligned_rdata_o = {L0_buffer[1][15:0], L0_buffer[0][31:16] }; unaligned_valid_o = valid_o; end
2'b10: begin unaligned_rdata_o = {L0_buffer[2][15:0], L0_buffer[1][31:16] }; unaligned_valid_o = valid_o; end
2'b11: begin unaligned_rdata_o = {L0_buffer[3][15:0], L0_buffer[2][31:16] }; unaligned_valid_o = valid_o; end
endcase // addr_o
case(CS)
// wait for the first branch request before fetching any instructions
EMPTY:
begin
instr_req_o = branch_i;
@ -126,13 +127,9 @@ module prefetch_L0_buffer
begin
if(instr_gnt_i)
begin
NS = WAIT_RVALID;
end
else
begin
NS = WAIT_GNT;
end
end
else
begin
@ -150,13 +147,9 @@ module prefetch_L0_buffer
instr_addr_o = {addr_i[31:4],4'b0000};
if(instr_gnt_i)
begin
NS = WAIT_RVALID;
end
else
begin
NS = WAIT_GNT;
end
end
else
begin
@ -166,25 +159,21 @@ module prefetch_L0_buffer
end
else // else (branch_i)
begin
valid_o = instr_rvalid_i;
valid_o = instr_rvalid_i;
case(pointer_cs)
2'b00:
begin
unaligned_rdata_o = { instr_rdata_i[0][15:0], L0_buffer[3][31:16] };
unaligned_rdata_o = { instr_rdata_i[0][15:0], L0_buffer[3][31:16] };
if(valid_L0_buffer)
begin
unaligned_valid_o = instr_rvalid_i;
end
unaligned_valid_o = instr_rvalid_i;
else
begin
unaligned_valid_o = 1'b0;
end
unaligned_valid_o = 1'b0;
end
2'b01: begin unaligned_rdata_o = {instr_rdata_i[1][15:0], instr_rdata_i[0][31:16] }; unaligned_valid_o = instr_rvalid_i; end
2'b10: begin unaligned_rdata_o = {instr_rdata_i[2][15:0], instr_rdata_i[1][31:16] }; unaligned_valid_o = instr_rvalid_i; end
2'b11: begin unaligned_rdata_o = {instr_rdata_i[3][15:0], instr_rdata_i[2][31:16] }; unaligned_valid_o = instr_rvalid_i; end
2'b01: begin unaligned_rdata_o = {instr_rdata_i[1][15:0], instr_rdata_i[0][31:16] }; unaligned_valid_o = instr_rvalid_i; end
2'b10: begin unaligned_rdata_o = {instr_rdata_i[2][15:0], instr_rdata_i[1][31:16] }; unaligned_valid_o = instr_rvalid_i; end
2'b11: begin unaligned_rdata_o = {instr_rdata_i[3][15:0], instr_rdata_i[2][31:16] }; unaligned_valid_o = instr_rvalid_i; end
endcase // pointer_cs
if(instr_rvalid_i)
@ -201,13 +190,9 @@ module prefetch_L0_buffer
update_current_address = 1'b1;
if(instr_gnt_i)
begin
NS = WAIT_RVALID;
end
else
begin
NS = WAIT_GNT;
end
end
else
begin
@ -218,13 +203,9 @@ module prefetch_L0_buffer
begin
NS = VALID_L0;
if(ready_i)
begin
pointer_ns = pointer_cs + 1'b1;
end
else
begin
pointer_ns = pointer_cs;
end
end
end
else // still wait instr_rvalid_i
@ -234,15 +215,15 @@ module prefetch_L0_buffer
end
end //~WAIT_RVALID
VALID_L0:
begin
VALID_L0:
begin
valid_o = 1'b1;
rdata_o = L0_buffer[pointer_cs];
case(pointer_cs)
2'b00: begin unaligned_rdata_o = {L0_buffer[0][15:0], previous_chunk }; unaligned_valid_o = valid_previous_chunk; end
2'b01: begin unaligned_rdata_o = {L0_buffer[1][15:0], L0_buffer[0][31:16] }; unaligned_valid_o = 1'b1; end
2'b10: begin unaligned_rdata_o = {L0_buffer[2][15:0], L0_buffer[1][31:16] }; unaligned_valid_o = 1'b1; end
2'b11: begin unaligned_rdata_o = {L0_buffer[3][15:0], L0_buffer[2][31:16] }; unaligned_valid_o = 1'b1; end
2'b00: begin unaligned_rdata_o = {L0_buffer[0][15:0], previous_chunk }; unaligned_valid_o = valid_previous_chunk; end
2'b01: begin unaligned_rdata_o = {L0_buffer[1][15:0], L0_buffer[0][31:16] }; unaligned_valid_o = 1'b1; end
2'b10: begin unaligned_rdata_o = {L0_buffer[2][15:0], L0_buffer[1][31:16] }; unaligned_valid_o = 1'b1; end
2'b11: begin unaligned_rdata_o = {L0_buffer[3][15:0], L0_buffer[2][31:16] }; unaligned_valid_o = 1'b1; end
endcase // pointer_cs
@ -250,14 +231,11 @@ module prefetch_L0_buffer
begin
instr_req_o = 1'b1;
instr_addr_o = {addr_i[31:4],4'b0000};
if(instr_gnt_i)
begin
NS = WAIT_RVALID;
end
else
begin
NS = WAIT_GNT;
end
end
else
begin
@ -265,24 +243,20 @@ module prefetch_L0_buffer
begin
if( &pointer_cs ) // we are dispathing the last packet, therefore prefetch the next cache line
begin
instr_req_o = 1'b1;
instr_req_o = 1'b1;
instr_addr_o = current_address + 5'h10;
update_current_address = 1'b1;
pointer_ns = '0;
if(instr_gnt_i)
begin
NS = WAIT_RVALID;
end
else
begin
NS = WAIT_GNT;
end
end
else
begin
pointer_ns = pointer_cs + 1'b1;
NS = VALID_L0;
NS = VALID_L0;
end
end
else // not ready, stay here!!!!
@ -290,7 +264,7 @@ module prefetch_L0_buffer
NS = VALID_L0;
end
end
end //~VALID_L0
end //~VALID_L0
WAIT_GNT:
begin
@ -300,46 +274,35 @@ module prefetch_L0_buffer
instr_addr_o = {addr_i[31:4],4'b0000};
if(instr_gnt_i)
begin
NS = WAIT_RVALID;
end
else
begin
NS = WAIT_GNT;
end
end
else
begin
instr_req_o = 1'b1;
instr_req_o = 1'b1;
instr_addr_o = current_address; // has been previously updated
if(instr_gnt_i)
begin
NS = WAIT_RVALID;
end
else
begin
NS = WAIT_GNT;
end
end
end //~WAIT_GNT
WAIT_ABORTED:
begin
clear_buffer = 1'b1;
if(instr_rvalid_i)
begin
instr_req_o = 1'b1;
instr_addr_o = current_address;
if(instr_gnt_i)
begin
NS = WAIT_RVALID;
end
else
begin
NS = WAIT_GNT;
end
end
else
begin