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did some cleanup relating to the generation of the VALID_INSTRUCTION signal

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(Tim) Efthimis Kritikos 2023-11-01 05:00:09 +00:00
parent 3a63e916f5
commit 557d160be6
2 changed files with 127 additions and 113 deletions
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116
system/biu.v
View File

@ -23,7 +23,8 @@
`define BIU_HALT 4'b0000
`define BIU_NEXT_ACTION 4'b0001
`define BIU_READ 4'b0010
`define BIU_RESET 4'b0011
`define BIU_RESET1 4'b0011
`define BIU_RESET2 4'b1111
`define BIU_PUT_BYTE 4'b0100
`define BIU_PUT_UNALIGNED_16BIT_DATA 4'b0101
@ -86,13 +87,15 @@ reg [`L1_CACHE_SIZE-1:0] FIFO_end; /*exclusive*/
wire [`L1_CACHE_SIZE-1:0] FIFO_SIZE = FIFO_end-FIFO_start;
reg [3:0] biu_state;
reg sane;
always @(negedge reset) begin
biu_state <= `BIU_HALT;
write <= 1;
sane <= 0;
end
always @(posedge reset) begin
biu_state <= `BIU_RESET;
biu_state <= `BIU_RESET1;
/* verilator lint_off BLKSEQ */
FIFO_start = `L1_CACHE_SIZE'b0;
FIFO_end = `L1_CACHE_SIZE'b0;
@ -109,10 +112,6 @@ assign external_address_bus= func ? INSTRUCTION_ADDRESS : DATA_ADDRESS ;
always @(posedge clock) begin
if ( jump_req_latch ) begin
/* verilator lint_off BLKSEQ */
FIFO_start = 0;
FIFO_end = 0;
/* verilator lint_on BLKSEQ */
INSTRUCTION_ADDRESS <= { 4'b0 , ADDRESS_INPUT };
INSTRUCTION_LOCATION <= ADDRESS_INPUT;
func <= 1;
@ -155,45 +154,6 @@ always @(posedge clock) begin
end
end
`ifdef EARLY_VALID_INSTRUCTION
if(FIFO_start==FIFO_end) begin
/*TODO: I would use FIFO_SIZE==0 here or better yet add an else at the
end but since FIFO_start and FIFO_end are updated in a blocking
manner it seems that the assign statement updating FIFO_SIZE
doesn't work. PLEASE CLEAN UP THIS MESS */
VALID_INSTRUCTION <= 0;
end else if((Isit1==1) && (FIFO_SIZE!=0))begin
VALID_INSTRUCTION <= 1;
INSTRUCTION[31:24] <= INPUT_FIFO[FIFO_start];
end else if((fifoIsize==2) && (FIFO_SIZE > `L1_CACHE_SIZE'd1))begin
VALID_INSTRUCTION <= 1;
INSTRUCTION[31:24] <= INPUT_FIFO[FIFO_start];
INSTRUCTION[23:16] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd1];
end else if((fifoIsize==3) && (FIFO_SIZE > `L1_CACHE_SIZE'd2))begin
VALID_INSTRUCTION <= 1;
INSTRUCTION[31:24] <= INPUT_FIFO[FIFO_start];
INSTRUCTION[23:16] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd1];
INSTRUCTION[15: 8] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd2];
end else if(FIFO_SIZE > `L1_CACHE_SIZE'd3)begin
VALID_INSTRUCTION <= 1;
INSTRUCTION[31:24] <= INPUT_FIFO[FIFO_start];
INSTRUCTION[23:16] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd1];
INSTRUCTION[15: 8] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd2];
INSTRUCTION[ 7: 0] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd3];
end
`else
if(FIFO_start==FIFO_end) begin
/*TODO: Same as on the first statment on the other side of the `ifdef */
VALID_INSTRUCTION <= 0;
end else if(FIFO_SIZE>`L1_CACHE_SIZE'd3)begin
VALID_INSTRUCTION <= 1;
INSTRUCTION[31:24] <= INPUT_FIFO[FIFO_start];
INSTRUCTION[23:16] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd1];
INSTRUCTION[15: 8] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd2];
INSTRUCTION[ 7: 0] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd3];
end
`endif
end
@ -201,21 +161,21 @@ always @(posedge clock) begin
/*************** INSTRUCTION FIFO READ ***************/
`BIU_READ: begin
if(INSTRUCTION_ADDRESS[0:0]==0 && FIFO_SIZE<{{(`L1_CACHE_SIZE-1){1'b1}},1'b0})begin
INPUT_FIFO[FIFO_end] <= external_data_bus[7:0];
INPUT_FIFO[FIFO_end+`L1_CACHE_SIZE'd1] <= external_data_bus[15:8];
/* verilator lint_off BLKSEQ */
INPUT_FIFO[FIFO_end] = external_data_bus[7:0];
INPUT_FIFO[FIFO_end+`L1_CACHE_SIZE'd1] = external_data_bus[15:8];
FIFO_end = FIFO_end+`L1_CACHE_SIZE'd2;
/* verilator lint_on BLKSEQ */
INSTRUCTION_ADDRESS <= INSTRUCTION_ADDRESS+20'd2;
end else if(INSTRUCTION_ADDRESS[0:0]==0)begin
INPUT_FIFO[FIFO_end] <= external_data_bus[7:0];
/* verilator lint_off BLKSEQ */
INPUT_FIFO[FIFO_end] = external_data_bus[7:0];
FIFO_end = FIFO_end+`L1_CACHE_SIZE'd1;
/* verilator lint_on BLKSEQ */
INSTRUCTION_ADDRESS <= INSTRUCTION_ADDRESS+20'd1;
end else begin
INPUT_FIFO[FIFO_end] <= external_data_bus[15:8];
/* verilator lint_off BLKSEQ */
INPUT_FIFO[FIFO_end] = external_data_bus[15:8];
FIFO_end = FIFO_end+`L1_CACHE_SIZE'd1;
/* verilator lint_on BLKSEQ */
INSTRUCTION_ADDRESS <= INSTRUCTION_ADDRESS+20'd1;
@ -320,7 +280,11 @@ always @(posedge clock) begin
end
/*************** HOUSE KEEPING ***************/
`BIU_RESET: begin
`BIU_RESET1: begin
biu_state <= `BIU_RESET2;
VALID_DATA <= 0;
end
`BIU_RESET2: begin
/* verilator lint_off BLKSEQ */
FIFO_start = `L1_CACHE_SIZE'b0;
FIFO_end = `L1_CACHE_SIZE'b0;
@ -328,9 +292,9 @@ always @(posedge clock) begin
biu_state <= `BIU_NEXT_ACTION;
INSTRUCTION_ADDRESS <= 20'h0FFF0;
INSTRUCTION_LOCATION <= 16'hFFF0;
VALID_INSTRUCTION <= 0;
VALID_DATA <= 0;
DATA_DIR <= 0;
sane<=1;
end
default: begin
biu_state <= `BIU_NEXT_ACTION;/*Should be unreachable*/
@ -362,6 +326,11 @@ always @( valid_instruction_ack ) begin
FIFO_start = FIFO_start + {{`L1_CACHE_SIZE-3{1'b0}},Isize};
/* verilator lint_on BLKSEQ */
INSTRUCTION_LOCATION <= INSTRUCTION_LOCATION + {13'd0,Isize};
end
always @( FIFO_start or FIFO_end ) begin
if(sane==1) begin
if(VALID_INSTRUCTION == 1 ) begin
`ifdef DOUBLE_INSTRUCTION_LOAD
if(FIFO_SIZE>`L1_CACHE_SIZE'd3+{{`L1_CACHE_SIZE-3{1'b0}},Isize})begin
if((fifoIsize2==2) && (FIFO_SIZE > `L1_CACHE_SIZE'd1+{{`L1_CACHE_SIZE-3{1'b0}},fifoIsize}))begin
@ -387,9 +356,54 @@ always @( valid_instruction_ack ) begin
`else
VALID_INSTRUCTION <= 0;
`endif
end else begin
//$display("trig fifoIsize=%d %d/%d [%02x %02x]",fifoIsize,FIFO_start,FIFO_end,INPUT_FIFO[FIFO_start],INPUT_FIFO[FIFO_start+1]);
`ifdef EARLY_VALID_INSTRUCTION
if(FIFO_start==FIFO_end) begin
/*TODO: I would use FIFO_SIZE==0 here or better yet add an else at the
end but since FIFO_start and FIFO_end are updated in a blocking
manner it seems that the assign statement updating FIFO_SIZE
doesn't work. PLEASE CLEAN UP THIS MESS */
VALID_INSTRUCTION <= 0;
end else if((Isit1==1) && (FIFO_SIZE!=0))begin
VALID_INSTRUCTION <= 1;
INSTRUCTION[31:24] <= INPUT_FIFO[FIFO_start];
end else if((fifoIsize==2) && (FIFO_SIZE > `L1_CACHE_SIZE'd1))begin
VALID_INSTRUCTION <= 1;
INSTRUCTION[31:24] <= INPUT_FIFO[FIFO_start];
INSTRUCTION[23:16] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd1];
end else if((fifoIsize==3) && (FIFO_SIZE > `L1_CACHE_SIZE'd2))begin
VALID_INSTRUCTION <= 1;
INSTRUCTION[31:24] <= INPUT_FIFO[FIFO_start];
INSTRUCTION[23:16] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd1];
INSTRUCTION[15: 8] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd2];
end else if(FIFO_SIZE > `L1_CACHE_SIZE'd3)begin
VALID_INSTRUCTION <= 1;
INSTRUCTION[31:24] <= INPUT_FIFO[FIFO_start];
INSTRUCTION[23:16] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd1];
INSTRUCTION[15: 8] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd2];
INSTRUCTION[ 7: 0] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd3];
end
`else
if(FIFO_start==FIFO_end) begin
/*TODO: Same as on the first statment on the other side of the `ifdef */
VALID_INSTRUCTION <= 0;
end else if(FIFO_SIZE>`L1_CACHE_SIZE'd3)begin
VALID_INSTRUCTION <= 1;
INSTRUCTION[31:24] <= INPUT_FIFO[FIFO_start];
INSTRUCTION[23:16] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd1];
INSTRUCTION[15: 8] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd2];
INSTRUCTION[ 7: 0] <= INPUT_FIFO[FIFO_start+`L1_CACHE_SIZE'd3];
end
`endif
end
end
end
always @( posedge jump_req ) begin
/* verilator lint_off BLKSEQ */
FIFO_start = FIFO_end ;
/* verilator lint_on BLKSEQ */
jump_req_latch <= 1;
DATA_DIR <= 1;
VALID_INSTRUCTION <= 0;

76
system/decoder.v
View File

@ -1031,36 +1031,36 @@ endmodule
module InstrSize ( input [10:0] IN, output reg [2:0] VERDICT );
always @( IN ) begin
casez(IN)
11'b0000_010?_??? : VERDICT <= 3'd2+{2'b0,IN[3:3]}; /* ADD - Add Immediate word/byte to accumulator */
11'b1000_00??_101 : VERDICT <= 3'd3+{2'b0,(IN[4:3]==2'b01)}; /* SUB - Subtract immediate word/byte from register/memory */
11'b1000_00??_000 : VERDICT <= 3'd3+{2'b0,(IN[4:3]==2'b01)}; /* ADD - Add Immediate word/byte to register/memory */
11'b1000_00??_111 : VERDICT <= 3'd3+{2'b0,(IN[4:3]==2'b01)}; /* CMP - compare Immediate with register / memory */
11'b1011_????_??? : VERDICT <= 3'd2+{2'b0,IN[6:6]}; /* MOV - Move Immediate byte to register */
11'b1000_10??_??? : VERDICT <= 3'd2; /* MOV - Reg/Mem to/from register */
11'b0100_????_??? : VERDICT <= 3'd1; /* DEC - Decrement Register | INC - Increment Register */
11'b1111_111?_00? : VERDICT <= 3'd2; /* INC - Register/Memory | DEC - Register/Memory */
11'b1111_0100_??? : VERDICT <= 3'd1; /* HLT - Halt */
11'b0011_110?_??? : VERDICT <= 3'd2+{2'b0,IN[3:3]}; /* CMP - Compare Immediate with accumulator */
11'b0111_????_??? : VERDICT <= 3'd2; /* Conditional relative jumps ( JE/JZ, JS/JNS ... ) */
11'b1110_1011_??? : VERDICT <= 3'd2; /* JMP - Unconditional jump direct within segment (short) */
11'b1110_1000_??? : VERDICT <= 3'd3; /* CALL - Direct call within segment */
11'b1100_0011_??? : VERDICT <= 3'd1; /* RET - Return from call within segment */
11'b1010_101?_??? : VERDICT <= 3'd1; /* STOS - Write byte/word to [DI] and increment accordingly */
11'b0101_0???_??? : VERDICT <= 3'd1; /* PUSH - SP-=2; [SP]=REG */
11'b1111_011?_000 : VERDICT <= 3'd3+{2'b0,IN[3:3]}; /* TEST - Bitwise AND affecting only flags */
11'b0101_1???_??? : VERDICT <= 3'd1; /* POP - REG=[SP]; SP+=2 */
11'b1111_1111_100 : VERDICT <= 3'd2; /* JMP - Unconditional indirect within segment jump */
11'b1100_011?_000 : VERDICT <= 3'd3+{2'b0,IN[3:3]}; /* MOV - Move immediate to register/memory */
11'b1100_1101_??? : VERDICT <= 3'd2; /* INT - execute interrupt handler */
11'b1110_011?_??? : VERDICT <= 3'd2; /* OUT - write AL or AX to a defined output port */
11'b1100_1111_??? : VERDICT <= 3'd1; /* IRET - Return from interrupt */
11'b1000_000?_100 : VERDICT <= 3'd3+{2'b0,IN[3:3]}; /* AND - Bitwise AND immediate and register/mem */
11'b1000_000?_001 : VERDICT <= 3'd3+{2'b0,IN[3:3]}; /* OR - Bitwise OR immediate and register/mem */
11'b1010_100?_??? : VERDICT <= 3'd2+{2'b0,IN[3:3]}; /* TEST - Bitwise AND affecting only flags */
11'b0000_00??_??? : VERDICT <= 3'd2; /* ADD - Reg/memory with register to either */
11'b0010_10??_??? : VERDICT <= 3'd2; /* SUB - Reg/memory with register to either */
11'b0011_10??_??? : VERDICT <= 3'd2; /* CMP - Compare Register/memory and register */
default:begin end
11'b0000_010?_??? : VERDICT = 3'd2+{2'b0,IN[3:3]}; /* ADD - Add Immediate word/byte to accumulator */
11'b1000_00??_101 : VERDICT = 3'd3+{2'b0,(IN[4:3]==2'b01)}; /* SUB - Subtract immediate word/byte from register/memory */
11'b1000_00??_000 : VERDICT = 3'd3+{2'b0,(IN[4:3]==2'b01)}; /* ADD - Add Immediate word/byte to register/memory */
11'b1000_00??_111 : VERDICT = 3'd3+{2'b0,(IN[4:3]==2'b01)}; /* CMP - compare Immediate with register / memory */
11'b1011_????_??? : VERDICT = 3'd2+{2'b0,IN[6:6]}; /* MOV - Move Immediate byte to register */
11'b1000_10??_??? : VERDICT = 3'd2; /* MOV - Reg/Mem to/from register */
11'b0100_????_??? : VERDICT = 3'd1; /* DEC - Decrement Register | INC - Increment Register */
11'b1111_111?_00? : VERDICT = 3'd2; /* INC - Register/Memory | DEC - Register/Memory */
11'b1111_0100_??? : VERDICT = 3'd1; /* HLT - Halt */
11'b0011_110?_??? : VERDICT = 3'd2+{2'b0,IN[3:3]}; /* CMP - Compare Immediate with accumulator */
11'b0111_????_??? : VERDICT = 3'd2; /* Conditional relative jumps ( JE/JZ, JS/JNS ... ) */
11'b1110_1011_??? : VERDICT = 3'd2; /* JMP - Unconditional jump direct within segment (short) */
11'b1110_1000_??? : VERDICT = 3'd3; /* CALL - Direct call within segment */
11'b1100_0011_??? : VERDICT = 3'd1; /* RET - Return from call within segment */
11'b1010_101?_??? : VERDICT = 3'd1; /* STOS - Write byte/word to [DI] and increment accordingly */
11'b0101_0???_??? : VERDICT = 3'd1; /* PUSH - SP-=2; [SP]=REG */
11'b1111_011?_000 : VERDICT = 3'd3+{2'b0,IN[3:3]}; /* TEST - Bitwise AND affecting only flags */
11'b0101_1???_??? : VERDICT = 3'd1; /* POP - REG=[SP]; SP+=2 */
11'b1111_1111_100 : VERDICT = 3'd2; /* JMP - Unconditional indirect within segment jump */
11'b1100_011?_000 : VERDICT = 3'd3+{2'b0,IN[3:3]}; /* MOV - Move immediate to register/memory */
11'b1100_1101_??? : VERDICT = 3'd2; /* INT - execute interrupt handler */
11'b1110_011?_??? : VERDICT = 3'd2; /* OUT - write AL or AX to a defined output port */
11'b1100_1111_??? : VERDICT = 3'd1; /* IRET - Return from interrupt */
11'b1000_000?_100 : VERDICT = 3'd3+{2'b0,IN[3:3]}; /* AND - Bitwise AND immediate and register/mem */
11'b1000_000?_001 : VERDICT = 3'd3+{2'b0,IN[3:3]}; /* OR - Bitwise OR immediate and register/mem */
11'b1010_100?_??? : VERDICT = 3'd2+{2'b0,IN[3:3]}; /* TEST - Bitwise AND affecting only flags */
11'b0000_00??_??? : VERDICT = 3'd2; /* ADD - Reg/memory with register to either */
11'b0010_10??_??? : VERDICT = 3'd2; /* SUB - Reg/memory with register to either */
11'b0011_10??_??? : VERDICT = 3'd2; /* CMP - Compare Register/memory and register */
default: VERDICT = 3'd7;
endcase
end
endmodule
@ -1069,14 +1069,14 @@ endmodule
module Is1 ( input [7:0] IN, output reg VERDICT );
always @( IN ) begin
casez(IN)
8'b0100_???? : VERDICT <= 1; /* DEC - Decrement Register | INC - Increment Register */
8'b1111_0100 : VERDICT <= 1; /* HLT - Halt */
8'b1100_0011 : VERDICT <= 1; /* RET - Return from call within segment */
8'b1010_101? : VERDICT <= 1; /* STOS - Write byte/word to [DI] and increment accordingly */
8'b0101_0??? : VERDICT <= 1; /* PUSH - SP-=2; [SP]=REG */
8'b0101_1??? : VERDICT <= 1; /* POP - REG=[SP]; SP+=2 */
8'b1100_1111 : VERDICT <= 1; /* IRET - Return from interrupt */
default:begin VERDICT<= 0; end
8'b0100_???? : VERDICT = 1; /* DEC - Decrement Register | INC - Increment Register */
8'b1111_0100 : VERDICT = 1; /* HLT - Halt */
8'b1100_0011 : VERDICT = 1; /* RET - Return from call within segment */
8'b1010_101? : VERDICT = 1; /* STOS - Write byte/word to [DI] and increment accordingly */
8'b0101_0??? : VERDICT = 1; /* PUSH - SP-=2; [SP]=REG */
8'b0101_1??? : VERDICT = 1; /* POP - REG=[SP]; SP+=2 */
8'b1100_1111 : VERDICT = 1; /* IRET - Return from interrupt */
default:begin VERDICT = 0; end
endcase
end
endmodule