Add addr_decode and testbench

hw/fpga/addr_decode.sv

@@ -0,0 +1,10 @@
+module addr_decode(
+    input logic [15:0] addr,
+    output logic ram_cs,
+    output logic rom_cs
+);
+
+assign rom_cs = addr[15];
+assign ram_cs = ~addr[15];
+
+endmodule

hw/fpga/hvl/cs_testbench.sv

@@ -0,0 +1,32 @@
+module testbench();
+
+timeunit 10ns;
+
+timeprecision 1ns;
+
+logic [15:0] addr;
+logic ram_cs;
+logic rom_cs;
+
+
+addr_decode dut(.*);
+
+initial begin : TEST_VECTORS
+
+    for (int i = 0; i < 2**16; i++) begin
+        addr <= i;
+        #1
+        if (i < 2**15) begin
+            assert(ram_cs == '1)
+            else
+                $error("Bad CS! addr=%4x should have ram_cs!", addr);
+        end
+        if (i >= 2**15) begin
+            assert(rom_cs == '1)
+            else
+                $error("Bad CS! addr=%4x should have rom_cs!", addr);
+        end
+    end
+
+end
+endmodule

hw/fpga/simulation/modelsim/.gitignore

@@ -0,0 +1,23 @@
+# ignore ModelSim generated files and directories (temp files and so on)
+[_@]*
+
+# ignore compilation output of ModelSim
+*.mti
+*.dat
+*.dbs
+*.psm
+*.bak
+*.cmp
+*.jpg
+*.html
+*.bsf
+
+# ignore simulation output of ModelSim
+wlf*
+*.wlf
+*.vstf
+*.ucdb
+cov*/
+transcript*
+sc_dpiheader.h
+vsim.dbg

hw/fpga/simulation/modelsim/cs_testbench.do

@@ -0,0 +1,22 @@
+transcript on
+if {[file exists rtl_work]} {
+	vdel -lib rtl_work -all
+}
+vlib rtl_work
+vmap work rtl_work
+
+vlog -sv -work work  {../../addr_decode.sv}
+vlog -sv -work work  {../../hvl/cs_testbench.sv}
+
+vsim -t 1ps -L altera_ver -L lpm_ver -L sgate_ver -L altera_mf_ver -L altera_lnsim_ver -L stratixv_ver -L stratixv_hssi_ver -L stratixv_pcie_hip_ver -L rtl_work -L work -voptargs="+acc"  testbench
+
+onfinish stop
+run -all
+
+if { [coverage attribute -name TESTSTATUS -concise] == "1"} {
+    echo Warning
+    quit -f -code 0
+}
+
+quit -code [coverage attribute -name TESTSTATUS -concise]
+

hw/fpga/simulation/modelsim/modelsim.ini

@@ -0,0 +1,324 @@
+; Copyright 1991-2009 Mentor Graphics Corporation
+;
+; All Rights Reserved.
+;
+; THIS WORK CONTAINS TRADE SECRET AND PROPRIETARY INFORMATION WHICH IS THE PROPERTY OF 
+; MENTOR GRAPHICS CORPORATION OR ITS LICENSORS AND IS SUBJECT TO LICENSE TERMS.
+;   
+
+[Library]
+others = $MODEL_TECH/../modelsim.ini
+
+; Altera Primitive libraries
+;
+; VHDL Section
+;
+;
+; Verilog Section
+;
+
+work = rtl_work
+[vcom]
+; VHDL93 variable selects language version as the default. 
+; Default is VHDL-2002.
+; Value of 0 or 1987 for VHDL-1987.
+; Value of 1 or 1993 for VHDL-1993.
+; Default or value of 2 or 2002 for VHDL-2002.
+; Default or value of 3 or 2008 for VHDL-2008.
+VHDL93 = 2002
+
+; Show source line containing error. Default is off.
+; Show_source = 1
+
+; Turn off unbound-component warnings. Default is on.
+; Show_Warning1 = 0
+
+; Turn off process-without-a-wait-statement warnings. Default is on.
+; Show_Warning2 = 0
+
+; Turn off null-range warnings. Default is on.
+; Show_Warning3 = 0
+
+; Turn off no-space-in-time-literal warnings. Default is on.
+; Show_Warning4 = 0
+
+; Turn off multiple-drivers-on-unresolved-signal warnings. Default is on.
+; Show_Warning5 = 0
+
+; Turn off optimization for IEEE std_logic_1164 package. Default is on.
+; Optimize_1164 = 0
+
+; Turn on resolving of ambiguous function overloading in favor of the
+; "explicit" function declaration (not the one automatically created by
+; the compiler for each type declaration). Default is off.
+; The .ini file has Explicit enabled so that std_logic_signed/unsigned
+; will match the behavior of synthesis tools.
+Explicit = 1
+
+; Turn off acceleration of the VITAL packages. Default is to accelerate.
+; NoVital = 1
+
+; Turn off VITAL compliance checking. Default is checking on.
+; NoVitalCheck = 1
+
+; Ignore VITAL compliance checking errors. Default is to not ignore.
+; IgnoreVitalErrors = 1
+
+; Turn off VITAL compliance checking warnings. Default is to show warnings.
+; Show_VitalChecksWarnings = 0
+
+; Keep silent about case statement static warnings.
+; Default is to give a warning.
+; NoCaseStaticError = 1
+
+; Keep silent about warnings caused by aggregates that are not locally static.
+; Default is to give a warning.
+; NoOthersStaticError = 1
+
+; Turn off inclusion of debugging info within design units.
+; Default is to include debugging info.
+; NoDebug = 1
+
+; Turn off "Loading..." messages. Default is messages on.
+; Quiet = 1
+
+; Turn on some limited synthesis rule compliance checking. Checks only:
+;    -- signals used (read) by a process must be in the sensitivity list
+; CheckSynthesis = 1
+
+; Activate optimizations on expressions that do not involve signals,
+; waits, or function/procedure/task invocations. Default is off.
+; ScalarOpts = 1
+
+; Require the user to specify a configuration for all bindings,
+; and do not generate a compile time default binding for the
+; component. This will result in an elaboration error of
+; 'component not bound' if the user fails to do so. Avoids the rare
+; issue of a false dependency upon the unused default binding.
+; RequireConfigForAllDefaultBinding = 1
+
+; Inhibit range checking on subscripts of arrays. Range checking on
+; scalars defined with subtypes is inhibited by default.
+; NoIndexCheck = 1
+
+; Inhibit range checks on all (implicit and explicit) assignments to
+; scalar objects defined with subtypes.
+; NoRangeCheck = 1
+
+[vlog]
+
+; Turn off inclusion of debugging info within design units.
+; Default is to include debugging info.
+; NoDebug = 1
+
+; Turn off "loading..." messages. Default is messages on.
+; Quiet = 1
+
+; Turn on Verilog hazard checking (order-dependent accessing of global vars).
+; Default is off.
+; Hazard = 1
+
+; Turn on converting regular Verilog identifiers to uppercase. Allows case
+; insensitivity for module names. Default is no conversion.
+; UpCase = 1
+
+; Turn on incremental compilation of modules. Default is off.
+; Incremental = 1
+
+; Turns on lint-style checking.
+; Show_Lint = 1
+
+[vsim]
+; Simulator resolution
+; Set to fs, ps, ns, us, ms, or sec with optional prefix of 1, 10, or 100.
+Resolution = ps
+
+; User time unit for run commands
+; Set to default, fs, ps, ns, us, ms, or sec. The default is to use the
+; unit specified for Resolution. For example, if Resolution is 100ps,
+; then UserTimeUnit defaults to ps.
+; Should generally be set to default.
+UserTimeUnit = default
+
+; Default run length
+RunLength = 100
+
+; Maximum iterations that can be run without advancing simulation time
+IterationLimit = 5000
+
+; Directive to license manager:
+; vhdl          Immediately reserve a VHDL license
+; vlog          Immediately reserve a Verilog license
+; plus          Immediately reserve a VHDL and Verilog license
+; nomgc         Do not look for Mentor Graphics Licenses
+; nomti         Do not look for Model Technology Licenses
+; noqueue       Do not wait in the license queue when a license isn't available
+; viewsim	Try for viewer license but accept simulator license(s) instead
+;		of queuing for viewer license
+; License = plus
+
+; Stop the simulator after a VHDL/Verilog assertion message
+; 0 = Note  1 = Warning  2 = Error  3 = Failure  4 = Fatal
+BreakOnAssertion = 3
+
+; Assertion Message Format
+; %S - Severity Level 
+; %R - Report Message
+; %T - Time of assertion
+; %D - Delta
+; %I - Instance or Region pathname (if available)
+; %% - print '%' character
+; AssertionFormat = "** %S: %R\n   Time: %T  Iteration: %D%I\n"
+
+; Assertion File - alternate file for storing VHDL/Verilog assertion messages
+; AssertFile = assert.log
+
+; Default radix for all windows and commands...
+; Set to symbolic, ascii, binary, octal, decimal, hex, unsigned
+DefaultRadix = symbolic
+
+; VSIM Startup command
+; Startup = do startup.do
+
+; File for saving command transcript
+TranscriptFile = transcript
+
+; File for saving command history
+; CommandHistory = cmdhist.log
+
+; Specify whether paths in simulator commands should be described
+; in VHDL or Verilog format.
+; For VHDL, PathSeparator = /
+; For Verilog, PathSeparator = .
+; Must not be the same character as DatasetSeparator.
+PathSeparator = /
+
+; Specify the dataset separator for fully rooted contexts.
+; The default is ':'. For example, sim:/top
+; Must not be the same character as PathSeparator.
+DatasetSeparator = :
+
+; Disable VHDL assertion messages
+; IgnoreNote = 1
+; IgnoreWarning = 1
+; IgnoreError = 1
+; IgnoreFailure = 1
+
+; Default force kind. May be freeze, drive, deposit, or default
+; or in other terms, fixed, wired, or charged.
+; A value of "default" will use the signal kind to determine the
+; force kind, drive for resolved signals, freeze for unresolved signals
+; DefaultForceKind = freeze
+
+; If zero, open files when elaborated; otherwise, open files on
+; first read or write.  Default is 0.
+; DelayFileOpen = 1
+
+; Control VHDL files opened for write.
+;   0 = Buffered, 1 = Unbuffered
+UnbufferedOutput = 0
+
+; Control the number of VHDL files open concurrently.
+; This number should always be less than the current ulimit
+; setting for max file descriptors.
+;   0 = unlimited
+ConcurrentFileLimit = 40
+
+; Control the number of hierarchical regions displayed as
+; part of a signal name shown in the Wave window.
+; A value of zero tells VSIM to display the full name.
+; The default is 0.
+; WaveSignalNameWidth = 0
+
+; Turn off warnings from the std_logic_arith, std_logic_unsigned
+; and std_logic_signed packages.
+; StdArithNoWarnings = 1
+
+; Turn off warnings from the IEEE numeric_std and numeric_bit packages.
+; NumericStdNoWarnings = 1
+
+; Control the format of the (VHDL) FOR generate statement label
+; for each iteration.  Do not quote it.
+; The format string here must contain the conversion codes %s and %d,
+; in that order, and no other conversion codes.  The %s represents
+; the generate_label; the %d represents the generate parameter value
+; at a particular generate iteration (this is the position number if
+; the generate parameter is of an enumeration type).  Embedded whitespace
+; is allowed (but discouraged); leading and trailing whitespace is ignored.
+; Application of the format must result in a unique scope name over all
+; such names in the design so that name lookup can function properly.
+; GenerateFormat = %s__%d
+
+; Specify whether checkpoint files should be compressed.
+; The default is 1 (compressed).
+; CheckpointCompressMode = 0
+
+; List of dynamically loaded objects for Verilog PLI applications
+; Veriuser = veriuser.sl
+
+; Specify default options for the restart command. Options can be one
+; or more of: -force -nobreakpoint -nolist -nolog -nowave
+; DefaultRestartOptions = -force
+
+; HP-UX 10.20 ONLY - Enable memory locking to speed up large designs
+; (> 500 megabyte memory footprint). Default is disabled.
+; Specify number of megabytes to lock.
+; LockedMemory = 1000
+
+; Turn on (1) or off (0) WLF file compression.
+; The default is 1 (compress WLF file).
+; WLFCompress = 0
+
+; Specify whether to save all design hierarchy (1) in the WLF file
+; or only regions containing logged signals (0).
+; The default is 0 (save only regions with logged signals).
+; WLFSaveAllRegions = 1
+
+; WLF file time limit.  Limit WLF file by time, as closely as possible,
+; to the specified amount of simulation time.  When the limit is exceeded
+; the earliest times get truncated from the file.
+; If both time and size limits are specified the most restrictive is used.
+; UserTimeUnits are used if time units are not specified.
+; The default is 0 (no limit).  Example: WLFTimeLimit = {100 ms}
+; WLFTimeLimit = 0
+
+; WLF file size limit.  Limit WLF file size, as closely as possible,
+; to the specified number of megabytes.  If both time and size limits
+; are specified then the most restrictive is used.
+; The default is 0 (no limit).
+; WLFSizeLimit = 1000
+
+; Specify whether or not a WLF file should be deleted when the
+; simulation ends.  A value of 1 will cause the WLF file to be deleted.
+; The default is 0 (do not delete WLF file when simulation ends).
+; WLFDeleteOnQuit = 1
+
+; Automatic SDF compilation
+; Disables automatic compilation of SDF files in flows that support it.
+; Default is on, uncomment to turn off.
+; NoAutoSDFCompile = 1
+
+[lmc]
+
+[msg_system]
+; Change a message severity or suppress a message.
+; The format is: <msg directive> = <msg number>[,<msg number>...]
+; Examples:
+;   note = 3009
+;   warning = 3033
+;   error = 3010,3016
+;   fatal = 3016,3033
+;   suppress = 3009,3016,3043
+; The command verror <msg number> can be used to get the complete
+; description of a message.
+
+; Control transcripting of elaboration/runtime messages.
+; The default is to have messages appear in the transcript and 
+; recorded in the wlf file (messages that are recorded in the
+; wlf file can be viewed in the MsgViewer).  The other settings
+; are to send messages only to the transcript or only to the 
+; wlf file.  The valid values are
+;    both  {default}
+;    tran  {transcript only}
+;    wlf   {wlf file only}
+; msgmode = both

hw/fpga/super6502.sv

@@ -29,6 +29,22 @@ logic [7:0] cpu_data_out;
 assign cpu_data = cpu_rwb ? cpu_data_out : 'z;
 
 
+
+
+logic [7:0] rom_data_out;
+logic [7:0] ram_data_out;
+
+logic ram_cs;
+logic rom_cs;
+
+
+addr_decode decode(
+    .addr(cpu_addr),
+    .ram_cs(ram_cs),
+    .rom_cs(rom_cs)
+);
+
+ 
 logic [2:0] clk_count;
 always_ff @(posedge clk) begin
     clk_count <= clk_count + 3'b1;
@@ -38,17 +54,20 @@ always_ff @(posedge clk) begin
     end
 end
 
+
+
 always_comb begin
     if (ram_cs)
         cpu_data_out = ram_data_out;
-    else
+    else if (rom_cs)
         cpu_data_out = rom_data_out;
+    else
+        cpu_data_out = 'x;
 end
 
 
-logic [7:0] ram_data_out;
+
-logic ram_cs;
+
-assign ram_cs = ~cpu_addr[15];
 ram main_memory(
     .address(cpu_addr[14:0]),
     .clock(clk),
@@ -58,7 +77,6 @@ ram main_memory(
 );
 
 
-logic [7:0] rom_data_out;
 rom boot_rom(
     .address(cpu_addr[14:0]),
     .clock(clk),