From 7724e5f383cf5745cbef554565ba0a870e02a8ba Mon Sep 17 00:00:00 2001
From: "(Tim) Efthimis Kritikos" <efkf@firemail.cc>
Date: Wed, 10 May 2023 08:53:19 +0100
Subject: [PATCH] Removed deprecated BIU_NEXT_POSITION

---
 system/biu.v       | 23 +++++++----------------
 system/processor.v | 12 ++++++------
 2 files changed, 13 insertions(+), 22 deletions(-)

diff --git a/system/biu.v b/system/biu.v
index e73dbbb..90ba941 100644
--- a/system/biu.v
+++ b/system/biu.v
@@ -40,7 +40,7 @@
 module BIU (
 /*outside world*/ input clock, input reset, output reg [19:0] external_address_bus,
 /*             */ inout [15:0] external_data_bus,output reg read, output reg write,output reg BHE,output reg IOMEM,
-/*  internal   */ output reg [31:0] INSTRUCTION, output reg VALID_INSTRUCTION, output reg [15:0] INSTRUCTION_LOCATION, input [1:0] NEXT_POSITION,
+/*  internal   */ output reg [31:0] INSTRUCTION, output reg VALID_INSTRUCTION, output reg [15:0] INSTRUCTION_LOCATION, input jump_req,
 /*             */ input[15:0] ADDRESS_INPUT, inout [15:0] DATA, input write_request, input read_request, input Wbit, output reg VALID_DATA, input MEM_OR_IO,
 /*             */ input [`PROC_STATE_BITS-1:0] proc_state, input SIMPLE_MICRO
 	);
@@ -70,7 +70,7 @@ always @(posedge reset) begin
 	biu_state <= `BIU_RESET;
 end
 
-reg jump_req;
+reg jump_req_latch;
 
 reg func;
 reg [19:0]INSTRUCTION_ADDRESS;
@@ -81,7 +81,7 @@ assign external_address_bus= func? INSTRUCTION_ADDRESS : DATA_ADDRESS ;
 
 /* Read into the FIFO */
 always @(posedge clock) begin
-	if ( jump_req ) begin
+	if ( jump_req_latch ) begin
 		/* verilator lint_off BLKSEQ */
 		FIFO_start = 0;
 		/* verilator lint_on BLKSEQ */
@@ -89,7 +89,7 @@ always @(posedge clock) begin
 		INSTRUCTION_ADDRESS <= { 4'b0 , ADDRESS_INPUT };
 		INSTRUCTION_LOCATION <= ADDRESS_INPUT;
 		func <= 1;
-		jump_req <= 0;
+		jump_req_latch <= 0;
 		if (biu_state==`BIU_READ)
 			biu_state <= `BIU_NEXT_ACTION;
 	end else begin
@@ -330,18 +330,9 @@ always @( negedge SIMPLE_MICRO ) begin
 	was_simple <= 1;
 end
 
-always @( NEXT_POSITION ) begin
-	case(NEXT_POSITION)
-		2'b00:begin end /* no action */
-		2'b01:begin /* Next instruction */
-		end
-		2'b10:begin /* Jump to specific location based on register */
-			jump_req <= 1;
-			VALID_INSTRUCTION <= 0;
-		end
-		2'b11:begin /* Jump to absolute location */
-		end
-	endcase
+always @( posedge jump_req ) begin
+	jump_req_latch <= 1;
+	VALID_INSTRUCTION <= 0;
 end
 
 endmodule
diff --git a/system/processor.v b/system/processor.v
index daef6c8..78cf3f1 100644
--- a/system/processor.v
+++ b/system/processor.v
@@ -37,7 +37,7 @@ reg [`PROC_STATE_BITS-1:0] state;
 /*############ Bus Interface Unit ############################################### */
 
 wire [31:0] INSTRUCTION;
-reg [1:0] BIU_NEXT_POSITION;
+reg jump_req;
 wire VALID_INSTRUCTION;
 wire [15:0] INSTRUCTION_LOCATION;
 reg [15:0] BIU_ADDRESS_INPUT;
@@ -49,7 +49,7 @@ wire BIU_VALID_DATA;
 
 BIU BIU(
 	clock,reset,external_address_bus,external_data_bus,read,write,BHE,IOMEM,
-	INSTRUCTION,VALID_INSTRUCTION,INSTRUCTION_LOCATION,BIU_NEXT_POSITION,BIU_ADDRESS_INPUT,BIU_DATA,biu_write_request,biu_read_request,Wbit,BIU_VALID_DATA,MEM_OR_IO,
+	INSTRUCTION,VALID_INSTRUCTION,INSTRUCTION_LOCATION,jump_req,BIU_ADDRESS_INPUT,BIU_DATA,biu_write_request,biu_read_request,Wbit,BIU_VALID_DATA,MEM_OR_IO,
 	state,SIMPLE_MICRO
 );
 assign BIU_DATA= biu_data_direction ? 16'hz : (memio_address_select?reg_read_port1_data:ALU_1O);
@@ -221,7 +221,7 @@ reg [23:0] INSTRUCTION_BUFFER;
 always @(posedge clock) begin
 	case(state)
 		`PROC_RESET:begin
-			BIU_NEXT_POSITION <= 0;
+			jump_req <= 0;
 			ucode_seq_addr <= `UCODE_NO_INSTRUCTION;
 			HALT <= 0;
 			ERROR <= `ERR_NO_ERROR;
@@ -284,11 +284,11 @@ always @(posedge clock) begin
 					ucode_seq_addr <= ucode_seq_addr_entry;
 					SIMPLE_MICRO <= 1;
 					/*keep state the same and rerun decode this time with all the data from the microcode rom*/
-					BIU_NEXT_POSITION <= 2'b00;
+					jump_req <= 0;
 				end else begin
 					state <= next_state;
 					if ( SIMPLE_MICRO == 0 ) begin
-						BIU_NEXT_POSITION <= 2'b00;
+						jump_req <= 0;
 					end
 				end
 			end
@@ -477,7 +477,7 @@ always @(posedge clock) begin
 				end
 				3'b101:begin /* Program Counter*/
 					BIU_ADDRESS_INPUT <= ALU_1O[15:0];
-					BIU_NEXT_POSITION <= 2'b10;
+					jump_req <= 1;
 					instruction_size_init <= 1;
 					if (ucode_seq_addr==`UCODE_NO_INSTRUCTION)
 						state <= `PROC_DE_STATE_ENTRY;