From 4015d4a5ab90f9b225275325d52262523c3cfc31 Mon Sep 17 00:00:00 2001 From: Clifford Wolf Date: Wed, 4 Nov 2015 01:12:37 +0100 Subject: [PATCH] Added scripts/cxxdemo/ --- README.md | 2 +- scripts/cxxdemo/.gitignore | 8 + scripts/cxxdemo/Makefile | 36 +++ scripts/cxxdemo/firmware.cc | 37 +++ scripts/cxxdemo/start.S | 48 ++++ scripts/cxxdemo/start.ld | 5 + scripts/cxxdemo/syscalls.c | 469 ++++++++++++++++++++++++++++++++++++ scripts/cxxdemo/testbench.v | 95 ++++++++ 8 files changed, 699 insertions(+), 1 deletion(-) create mode 100644 scripts/cxxdemo/.gitignore create mode 100644 scripts/cxxdemo/Makefile create mode 100644 scripts/cxxdemo/firmware.cc create mode 100644 scripts/cxxdemo/start.S create mode 100644 scripts/cxxdemo/start.ld create mode 100644 scripts/cxxdemo/syscalls.c create mode 100644 scripts/cxxdemo/testbench.v diff --git a/README.md b/README.md index 87c41c7..756ac72 100644 --- a/README.md +++ b/README.md @@ -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). 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) (a license that is similar in terms to the MIT license or the 2-clause BSD license). 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 +#include +#include +#include + +int main() +{ + printf("Hello World, C!\n"); + + std::cout << "Hello World, C++!" << std::endl; + + std::vector 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 +#include +#include +#include +#include +#include +#include +#include + +//------------------------------------------------------------------------ +// 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