Added scripts/cxxdemo/

7 files changed, 698 insertions, 0 deletions

diff --git a/scripts/cxxdemo/.gitignore b/scripts/cxxdemo/.gitignore
new file mode 100644
index 0000000..3c67fe4
--- /dev/null
+++ b/scripts/cxxdemo/.gitignore
@@ -0,0 +1,8 @@
+firmware.d
+firmware.elf
+firmware.hex
+firmware.o
+syscalls.o
+testbench.exe
+testbench.vcd
+start.elf
diff --git a/scripts/cxxdemo/Makefile b/scripts/cxxdemo/Makefile
new file mode 100644
index 0000000..3d10104
--- /dev/null
+++ b/scripts/cxxdemo/Makefile
@@ -0,0 +1,36 @@
+CXX = riscv32-unknown-elf-g++
+CC = riscv32-unknown-elf-gcc
+AS = riscv32-unknown-elf-gcc
+CXXFLAGS = -MD -Os -Wall -std=c++11
+CCFLAGS = -MD -Os -Wall -std=c++11
+LDFLAGS = -Wl,--gc-sections
+LDLIBS = -lstdc++
+
+test: testbench.exe firmware.hex
+	vvp -N testbench.exe
+
+testbench.exe: testbench.v ../../picorv32.v
+	iverilog -o testbench.exe testbench.v ../../picorv32.v
+	chmod -x testbench.exe
+
+firmware.hex: firmware.elf start.elf
+	riscv32-unknown-elf-objcopy -O verilog start.elf start.tmp
+	riscv32-unknown-elf-objcopy -O verilog firmware.elf firmware.tmp
+	cat start.tmp firmware.tmp > firmware.hex
+	rm -f start.tmp firmware.tmp
+
+firmware.elf: firmware.o syscalls.o
+	$(CC) $(LDFLAGS) -o $@ $^ $(LDLIBS)
+	chmod -x firmware.elf
+
+start.elf: start.S start.ld
+	$(CC) -nostdlib -o start.elf start.S -T start.ld $(LDLIBS)
+	chmod -x start.elf
+
+clean:
+	rm -f *.o *.d *.tmp start.elf
+	rm -f firmware.elf firmware.hex
+	rm -f testbench.exe testbench.vcd
+
+-include *.d
+.PHONY: test clean
diff --git a/scripts/cxxdemo/firmware.cc b/scripts/cxxdemo/firmware.cc
new file mode 100644
index 0000000..e0bddf0
--- /dev/null
+++ b/scripts/cxxdemo/firmware.cc
@@ -0,0 +1,37 @@
+#include <stdio.h>
+#include <iostream>
+#include <vector>
+#include <algorithm>
+
+int main()
+{
+	printf("Hello World, C!\n");
+
+	std::cout << "Hello World, C++!" << std::endl;
+
+	std::vector<unsigned int> some_ints;
+	some_ints.push_back(0x48c9b3e4);
+	some_ints.push_back(0x79109b6a);
+	some_ints.push_back(0x16155039);
+	some_ints.push_back(0xa3635c9a);
+	some_ints.push_back(0x8d2f4702);
+	some_ints.push_back(0x38d232ae);
+	some_ints.push_back(0x93924a17);
+	some_ints.push_back(0x62b895cc);
+	some_ints.push_back(0x6130d459);
+	some_ints.push_back(0x837c8b44);
+	some_ints.push_back(0x3d59b4fe);
+	some_ints.push_back(0x444914d8);
+	some_ints.push_back(0x3a3dc660);
+	some_ints.push_back(0xe5a121ef);
+	some_ints.push_back(0xff00866d);
+	some_ints.push_back(0xb843b879);
+
+	std::sort(some_ints.begin(), some_ints.end());
+
+	for (auto n : some_ints)
+		std::cout << std::hex << n << std::endl;
+
+	std::cout << "All done." << std::endl;
+	return 0;
+}
diff --git a/scripts/cxxdemo/start.S b/scripts/cxxdemo/start.S
new file mode 100644
index 0000000..33114cc
--- /dev/null
+++ b/scripts/cxxdemo/start.S
@@ -0,0 +1,48 @@
+.section .text
+.global _ftext
+.global _pvstart
+
+_pvstart:
+/* zero-initialize all registers */
+addi x1, zero, 0
+addi x2, zero, 0
+addi x3, zero, 0
+addi x4, zero, 0
+addi x5, zero, 0
+addi x6, zero, 0
+addi x7, zero, 0
+addi x8, zero, 0
+addi x9, zero, 0
+addi x10, zero, 0
+addi x11, zero, 0
+addi x12, zero, 0
+addi x13, zero, 0
+addi x14, zero, 0
+addi x15, zero, 0
+addi x16, zero, 0
+addi x17, zero, 0
+addi x18, zero, 0
+addi x19, zero, 0
+addi x20, zero, 0
+addi x21, zero, 0
+addi x22, zero, 0
+addi x23, zero, 0
+addi x24, zero, 0
+addi x25, zero, 0
+addi x26, zero, 0
+addi x27, zero, 0
+addi x28, zero, 0
+addi x29, zero, 0
+addi x30, zero, 0
+addi x31, zero, 0
+
+/* set stack pointer */
+lui sp, %hi(4*1024*1024)
+addi sp, sp, %lo(4*1024*1024)
+
+/* push a zero on the stack */
+addi sp,sp,-4
+sw zero,0(sp)
+
+/* jump to libc init */
+j _ftext
diff --git a/scripts/cxxdemo/start.ld b/scripts/cxxdemo/start.ld
new file mode 100644
index 0000000..773eee2
--- /dev/null
+++ b/scripts/cxxdemo/start.ld
@@ -0,0 +1,5 @@
+SECTIONS {
+. = 0x00000000;
+.text : { *(.text) }
+_ftext = 0x00010000;
+}
diff --git a/scripts/cxxdemo/syscalls.c b/scripts/cxxdemo/syscalls.c
new file mode 100644
index 0000000..16f791f
--- /dev/null
+++ b/scripts/cxxdemo/syscalls.c
@@ -0,0 +1,469 @@
+// Based on riscv newlib libgloss/riscv/machine/syscall.h
+// Changes by Clifford Wolf
+
+//========================================================================
+// syscalls.c : Newlib operating system interface                       
+//========================================================================
+// This is the maven implementation of the narrow newlib operating
+// system interface. It is based on the minimum stubs in the newlib
+// documentation, the error stubs in libnosys, and the previous scale
+// implementation. Please do not include any additional system calls or
+// other functions in this file. Additional header and source files
+// should be in the machine subdirectory.
+//
+// Here is a list of the functions which make up the operating system
+// interface. The file management instructions execute syscall assembly
+// instructions so that a proxy kernel (or the simulator) can marshal up
+// the request to the host machine. The process management functions are
+// mainly just stubs since for now maven only supports a single process.
+//
+//  - File management functions
+//     + open   : (v) open file
+//     + lseek  : (v) set position in file
+//     + read   : (v) read from file
+//     + write  : (v) write to file
+//     + fstat  : (z) status of an open file
+//     + stat   : (z) status of a file by name
+//     + close  : (z) close a file
+//     + link   : (z) rename a file
+//     + unlink : (z) remote file's directory entry
+//
+//  - Process management functions
+//     + execve : (z) transfer control to new proc
+//     + fork   : (z) create a new process 
+//     + getpid : (v) get process id 
+//     + kill   : (z) send signal to child process
+//     + wait   : (z) wait for a child process
+//     
+//  - Misc functions
+//     + isatty : (v) query whether output stream is a terminal
+//     + times  : (z) timing information for current process
+//     + sbrk   : (v) increase program data space
+//     + _exit  : (-) exit program without cleaning up files
+//
+// There are two types of system calls. Those which return a value when
+// everything is okay (marked with (v) in above list) and those which
+// return a zero when everything is okay (marked with (z) in above
+// list). On an error (ie. when the error flag is 1) the return value is
+// always an errno which should correspond to the numbers in
+// newlib/libc/include/sys/errno.h 
+//
+// Note that really I think we are supposed to define versions of these
+// functions with an underscore prefix (eg. _open). This is what some of
+// the newlib documentation says, and all the newlib code calls the
+// underscore version. This is because technically I don't think we are
+// supposed to pollute the namespace with these function names. If you
+// define MISSING_SYSCALL_NAMES in xcc/src/newlib/configure.host
+// then xcc/src/newlib/libc/include/_syslist.h will essentially define
+// all of the underscore versions to be equal to the non-underscore
+// versions. I tried not defining MISSING_SYSCALL_NAMES, and newlib
+// compiled fine but libstdc++ complained about not being able to fine
+// write, read, etc. So for now we do not use underscores (and we do
+// define MISSING_SYSCALL_NAMES).
+//
+// See the newlib documentation for more information 
+// http://sourceware.org/newlib/libc.html#Syscalls
+
+#include <sys/stat.h>
+#include <sys/times.h>
+#include <sys/time.h>
+#include <sys/timeb.h>
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+#include <utime.h>
+
+//------------------------------------------------------------------------
+// environment                                                          
+//------------------------------------------------------------------------
+// A pointer to a list of environment variables and their values. For a
+// minimal environment, this empty list is adequate. We used to define
+// environ here but it is already defined in
+// xcc/src/newlib/libc/stdlib/environ.c so to avoid multiple definition
+// errors we have commented this out for now.
+//
+// char* __env[1] = { 0 };
+// char** environ = __env;
+              
+//------------------------------------------------------------------------
+// open                                                                 
+//------------------------------------------------------------------------
+// Open a file.
+
+int open(const char* name, int flags, int mode)
+{
+	errno = ENOENT;
+	return -1;
+}
+
+//------------------------------------------------------------------------
+// openat                                                                
+//------------------------------------------------------------------------
+// Open file relative to given directory
+int openat(int dirfd, const char* name, int flags, int mode)
+{
+	errno = ENOENT;
+	return -1;
+}
+
+//------------------------------------------------------------------------
+// lseek                                                                
+//------------------------------------------------------------------------
+// Set position in a file.
+
+off_t lseek(int file, off_t ptr, int dir)
+{
+	errno = ESPIPE;
+	return -1;
+}
+
+//----------------------------------------------------------------------
+// read                                                                 
+//----------------------------------------------------------------------
+// Read from a file.
+
+ssize_t read(int file, void *ptr, size_t len)
+{
+	// always EOF
+	return 0;
+}
+
+//------------------------------------------------------------------------
+// write                                                                
+//------------------------------------------------------------------------
+// Write to a file.
+
+ssize_t write(int file, const void *ptr, size_t len)
+{
+	unsigned int *p = (unsigned int*)0x10000000;
+	const void *eptr = ptr + len;
+	while (ptr != eptr)
+		*p = *(char*)(ptr++);
+	return len;
+}
+
+//------------------------------------------------------------------------
+// fstat                                                                
+//------------------------------------------------------------------------
+// Status of an open file. The sys/stat.h header file required is
+// distributed in the include subdirectory for this C library.
+
+int fstat(int file, struct stat *st)
+{
+	errno = ENOENT;
+	return -1;
+}
+
+//------------------------------------------------------------------------
+// stat                                                                 
+//------------------------------------------------------------------------
+// Status of a file (by name).
+
+int stat(const char *file, struct stat *st)
+{
+	errno = ENOENT;
+	return -1;
+}
+
+//------------------------------------------------------------------------
+// lstat                                                                 
+//------------------------------------------------------------------------
+// Status of a link (by name).
+
+int lstat(const char *file, struct stat *st)
+{
+	errno = ENOENT;
+	return -1;
+}
+
+//------------------------------------------------------------------------
+// fstatat                                                                 
+//------------------------------------------------------------------------
+// Status of a file (by name) in a given directory.
+
+int fstatat(int dirfd, const char *file, struct stat *st, int flags)
+{
+	errno = ENOENT;
+	return -1;
+}
+
+//------------------------------------------------------------------------
+// access                                                                 
+//------------------------------------------------------------------------
+// Permissions of a file (by name).
+
+int access(const char *file, int mode)
+{
+	errno = ENOENT;
+	return -1;
+}
+
+//------------------------------------------------------------------------
+// faccessat                                                                 
+//------------------------------------------------------------------------
+// Permissions of a file (by name) in a given directory.
+
+int faccessat(int dirfd, const char *file, int mode, int flags)
+{
+	errno = ENOENT;
+	return -1;
+}
+
+//------------------------------------------------------------------------
+// close                                                                
+//------------------------------------------------------------------------
+// Close a file.
+
+int close(int file) 
+{
+	// close is always ok
+	return 0;
+}
+
+//------------------------------------------------------------------------
+// link                                                                 
+//------------------------------------------------------------------------
+// Establish a new name for an existing file.
+
+int link(const char *old_name, const char *new_name)
+{
+	errno = ENOENT;
+	return -1;
+}
+
+//------------------------------------------------------------------------
+// unlink                                                               
+//------------------------------------------------------------------------
+// Remove a file's directory entry.
+
+int unlink(const char *name)
+{
+	errno = ENOENT;
+	return -1;
+}
+
+//------------------------------------------------------------------------
+// execve                                                               
+//------------------------------------------------------------------------
+// Transfer control to a new process. Minimal implementation for a
+// system without processes from newlib documentation.
+
+int execve(const char *name, char *const argv[], char *const env[])
+{
+	errno = ENOMEM;
+	return -1;
+}
+
+//------------------------------------------------------------------------
+// fork                                                                 
+//------------------------------------------------------------------------
+// Create a new process. Minimal implementation for a system without
+// processes from newlib documentation.
+
+int fork() 
+{
+	errno = EAGAIN;
+	return -1;
+}
+
+//------------------------------------------------------------------------
+// getpid                                                               
+//------------------------------------------------------------------------
+// Get process id. This is sometimes used to generate strings unlikely
+// to conflict with other processes. Minimal implementation for a
+// system without processes just returns 1.
+
+int getpid() 
+{
+	return 1;
+}
+
+//------------------------------------------------------------------------
+// kill                                                                 
+//------------------------------------------------------------------------
+// Send a signal. Minimal implementation for a system without processes
+// just causes an error.
+
+int kill(int pid, int sig)
+{
+	errno = EINVAL;
+	return -1;
+}
+
+//------------------------------------------------------------------------
+// wait                                                                 
+//------------------------------------------------------------------------
+// Wait for a child process. Minimal implementation for a system without
+// processes just causes an error.
+
+int wait(int *status)
+{
+	errno = ECHILD;
+	return -1;
+}
+
+//------------------------------------------------------------------------
+// isatty                                                               
+//------------------------------------------------------------------------
+// Query whether output stream is a terminal. For consistency with the
+// other minimal implementations, which only support output to stdout,
+// this minimal implementation is suggested by the newlib docs.
+
+int isatty(int file)
+{
+	return 1;
+}
+
+//------------------------------------------------------------------------
+// times                                                                
+//------------------------------------------------------------------------
+// Timing information for current process. From
+// newlib/libc/include/sys/times.h the tms struct fields are as follows:
+//
+//  - clock_t tms_utime  : user clock ticks
+//  - clock_t tms_stime  : system clock ticks
+//  - clock_t tms_cutime : children's user clock ticks
+//  - clock_t tms_cstime : children's system clock ticks
+//
+// Since maven does not currently support processes we set both of the
+// children's times to zero. Eventually we might want to separately
+// account for user vs system time, but for now we just return the total
+// number of cycles since starting the program.
+
+clock_t times(struct tms *buf)
+{
+	// when called for the first time, initialize t0
+	static struct timeval t0;
+	if (t0.tv_sec == 0)
+		gettimeofday(&t0, 0);
+
+	struct timeval t;
+	gettimeofday(&t, 0);
+
+	long long utime = (t.tv_sec - t0.tv_sec) * 1000000 + (t.tv_usec - t0.tv_usec);
+	buf->tms_utime = utime * CLOCKS_PER_SEC / 1000000;
+	buf->tms_stime = buf->tms_cstime = buf->tms_cutime = 0;
+
+	return -1;
+}
+
+//----------------------------------------------------------------------
+// gettimeofday                                                                 
+//----------------------------------------------------------------------
+// Get the current time.  Only relatively correct.
+
+int gettimeofday(struct timeval *tp, void *tzp)
+{
+	asm volatile ("sbreak");
+	__builtin_unreachable();
+}
+
+//----------------------------------------------------------------------
+// ftime                                                                 
+//----------------------------------------------------------------------
+// Get the current time.  Only relatively correct.
+
+int ftime(struct timeb *tp)
+{
+	tp->time = tp->millitm = 0;
+	return 0;
+}
+
+//----------------------------------------------------------------------
+// utime
+//----------------------------------------------------------------------
+// Stub.
+
+int utime(const char *path, const struct utimbuf *times)
+{
+	return -1;
+}
+
+//----------------------------------------------------------------------
+// chown
+//----------------------------------------------------------------------
+// Stub.
+
+int chown(const char *path, uid_t owner, gid_t group)
+{
+	return -1;
+}
+
+//----------------------------------------------------------------------
+// chmod
+//----------------------------------------------------------------------
+// Stub.
+
+int chmod(const char *path, mode_t mode)
+{
+	return -1;
+}
+
+//----------------------------------------------------------------------
+// chdir
+//----------------------------------------------------------------------
+// Stub.
+
+int chdir(const char *path)
+{
+	return -1;
+}
+
+//----------------------------------------------------------------------
+// getcwd
+//----------------------------------------------------------------------
+// Stub.
+
+char *getcwd(char *buf, size_t size)
+{
+	return NULL;
+}
+
+//----------------------------------------------------------------------
+// sysconf
+//----------------------------------------------------------------------
+// Get configurable system variables
+
+long sysconf(int name)
+{
+	switch (name) {
+	case _SC_CLK_TCK:
+		return CLOCKS_PER_SEC;
+	}
+
+	return -1;
+}
+
+//----------------------------------------------------------------------
+// sbrk                                                                 
+//----------------------------------------------------------------------
+// Increase program data space. As malloc and related functions depend
+// on this, it is useful to have a working implementation. The following
+// is suggested by the newlib docs and suffices for a standalone
+// system.
+
+void *sbrk(ptrdiff_t incr)
+{
+	extern unsigned char _end[];	// Defined by linker
+	static unsigned long heap_end;
+
+	if (heap_end == 0)
+		heap_end = (long)_end;
+
+	// if (syscall_errno(SYS_brk, heap_end + incr, 0, 0, 0) != heap_end + incr)
+	//	return (void *)-1;
+
+	heap_end += incr;
+	return (void *)(heap_end - incr);
+}
+
+//------------------------------------------------------------------------
+// _exit                                                                
+//------------------------------------------------------------------------
+// Exit a program without cleaning up files.
+
+void _exit(int exit_status)
+{
+	asm volatile ("sbreak");
+	__builtin_unreachable();
+}
diff --git a/scripts/cxxdemo/testbench.v b/scripts/cxxdemo/testbench.v
new file mode 100644
index 0000000..b8bed17
--- /dev/null
+++ b/scripts/cxxdemo/testbench.v
@@ -0,0 +1,95 @@
+`timescale 1 ns / 1 ps
+`undef VERBOSE_MEM
+`undef WRITE_VCD
+
+module testbench;
+	reg clk = 1;
+	reg resetn = 0;
+	wire trap;
+
+	always #5 clk = ~clk;
+
+	initial begin
+		repeat (100) @(posedge clk);
+		resetn <= 1;
+	end
+
+	wire mem_valid;
+	wire mem_instr;
+	reg mem_ready;
+	wire [31:0] mem_addr;
+	wire [31:0] mem_wdata;
+	wire [3:0] mem_wstrb;
+	reg  [31:0] mem_rdata;
+
+	picorv32 uut (
+		.clk         (clk        ),
+		.resetn      (resetn     ),
+		.trap        (trap       ),
+		.mem_valid   (mem_valid  ),
+		.mem_instr   (mem_instr  ),
+		.mem_ready   (mem_ready  ),
+		.mem_addr    (mem_addr   ),
+		.mem_wdata   (mem_wdata  ),
+		.mem_wstrb   (mem_wstrb  ),
+		.mem_rdata   (mem_rdata  )
+	);
+
+	localparam MEM_SIZE = 4*1024*1024;
+	reg [7:0] memory [0:MEM_SIZE-1];
+	initial $readmemh("firmware.hex", memory);
+
+	always @(posedge clk) begin
+		mem_ready <= 0;
+		if (mem_valid && !mem_ready) begin
+			mem_ready <= 1;
+			mem_rdata <= 'bx;
+			case (1)
+				mem_addr < MEM_SIZE: begin
+					if (|mem_wstrb) begin
+						if (mem_wstrb[0]) memory[mem_addr + 0] <= mem_wdata[ 7: 0];
+						if (mem_wstrb[1]) memory[mem_addr + 1] <= mem_wdata[15: 8];
+						if (mem_wstrb[2]) memory[mem_addr + 2] <= mem_wdata[23:16];
+						if (mem_wstrb[3]) memory[mem_addr + 3] <= mem_wdata[31:24];
+					end else begin
+						mem_rdata <= {memory[mem_addr+3], memory[mem_addr+2], memory[mem_addr+1], memory[mem_addr]};
+					end
+				end
+				mem_addr == 32'h 1000_0000: begin
+					$write("%c", mem_wdata[7:0]);
+				end
+			endcase
+		end
+		if (mem_valid && mem_ready) begin
+`ifdef VERBOSE_MEM
+			if (|mem_wstrb)
+				$display("WR: ADDR=%x DATA=%x MASK=%b", mem_addr, mem_wdata, mem_wstrb);
+			else
+				$display("RD: ADDR=%x DATA=%x%s", mem_addr, mem_rdata, mem_instr ? " INSN" : "");
+`endif
+			if (^mem_addr === 1'bx ||
+					(mem_wstrb[0] && ^mem_wdata[ 7: 0] == 1'bx) ||
+					(mem_wstrb[1] && ^mem_wdata[15: 8] == 1'bx) ||
+					(mem_wstrb[2] && ^mem_wdata[23:16] == 1'bx) ||
+					(mem_wstrb[3] && ^mem_wdata[31:24] == 1'bx)) begin
+				$display("CRITICAL UNDEF MEM TRANSACTION");
+				$finish;
+			end
+		end
+	end
+
+`ifdef WRITE_VCD
+	initial begin
+		$dumpfile("testbench.vcd");
+		$dumpvars(0, testbench);
+	end
+`endif
+
+	always @(posedge clk) begin
+		if (resetn && trap) begin
+			repeat (10) @(posedge clk);
+			$display("TRAP");
+			$finish;
+		end
+	end
+endmodule