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Added scripts/cxxdemo/

This commit is contained in:
Clifford Wolf 2015-11-04 01:12:37 +01:00
parent 8d9f048785
commit 4015d4a5ab
8 changed files with 699 additions and 1 deletions
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2
README.md
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@ -6,7 +6,7 @@ PicoRV32 is a CPU core that implements the [RISC-V RV32I Instruction Set](http:/
Tools (gcc, binutils, etc..) can be obtained via the [RISC-V Website](http://riscv.org/download.html#tab_tools). Tools (gcc, binutils, etc..) can be obtained via the [RISC-V Website](http://riscv.org/download.html#tab_tools).
The examples bundled with PicoRV32 (such as the firmware for `make test`) expect a `riscv32-unknown-elf-` toolchain The examples bundled with PicoRV32 (such as the firmware for `make test`) expect a `riscv32-unknown-elf-` toolchain
(see [build instructions below](#building-a-pure-rv32i-toolchain)) installed in `$PATH`. installed in `$PATH` (see [build instructions below](#building-a-pure-rv32i-toolchain)).
PicoRV32 is free and open hardware licensed under the [ISC license](http://en.wikipedia.org/wiki/ISC_license) PicoRV32 is free and open hardware licensed under the [ISC license](http://en.wikipedia.org/wiki/ISC_license)
(a license that is similar in terms to the MIT license or the 2-clause BSD license). (a license that is similar in terms to the MIT license or the 2-clause BSD license).

8
scripts/cxxdemo/.gitignore vendored Normal file
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firmware.d
firmware.elf
firmware.hex
firmware.o
syscalls.o
testbench.exe
testbench.vcd
start.elf

36
scripts/cxxdemo/Makefile Normal file
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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

37
scripts/cxxdemo/firmware.cc Normal file
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#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;
}

48
scripts/cxxdemo/start.S Normal file
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.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

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scripts/cxxdemo/start.ld Normal file
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SECTIONS {
. = 0x00000000;
.text : { *(.text) }
_ftext = 0x00010000;
}

469
scripts/cxxdemo/syscalls.c Normal file
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@ -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();
}

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`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