Now using a truly minimalist syscalls.c

2 files changed, 96 insertions, 844 deletions

diff --git a/scripts/csmith/syscalls.c b/scripts/csmith/syscalls.c
index 16f791f..f12b07e 100644
--- a/scripts/csmith/syscalls.c
+++ b/scripts/csmith/syscalls.c
@@ -1,447 +1,80 @@
+// An extremely minimalist syscalls.c for newlib
 // 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
+// Written by Clifford Wolf.
 
 #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.
+#include <errno.h>
 
-off_t lseek(int file, off_t ptr, int dir)
-{
-	errno = ESPIPE;
-	return -1;
+#define UNIMPL_FUNC(_f) ".globl " #_f "\n.type " #_f ", @function\n" #_f ":\n"
+
+asm (
+	".text\n"
+	".align 2\n"
+	UNIMPL_FUNC(open)
+	UNIMPL_FUNC(openat)
+	UNIMPL_FUNC(lseek)
+	UNIMPL_FUNC(stat)
+	UNIMPL_FUNC(lstat)
+	UNIMPL_FUNC(fstatat)
+	UNIMPL_FUNC(isatty)
+	UNIMPL_FUNC(access)
+	UNIMPL_FUNC(faccessat)
+	UNIMPL_FUNC(link)
+	UNIMPL_FUNC(unlink)
+	UNIMPL_FUNC(execve)
+	UNIMPL_FUNC(getpid)
+	UNIMPL_FUNC(fork)
+	UNIMPL_FUNC(kill)
+	UNIMPL_FUNC(wait)
+	UNIMPL_FUNC(times)
+	UNIMPL_FUNC(gettimeofday)
+	UNIMPL_FUNC(ftime)
+	UNIMPL_FUNC(utime)
+	UNIMPL_FUNC(chown)
+	UNIMPL_FUNC(chmod)
+	UNIMPL_FUNC(chdir)
+	UNIMPL_FUNC(getcwd)
+	UNIMPL_FUNC(sysconf)
+	"j unimplemented_syscall\n"
+);
+
+void unimplemented_syscall()
+{
+	const char *p = "Unimplemented system call called!\n";
+	while (*p)
+		*(volatile int*)0x10000000 = *(p++);
+	asm volatile ("sbreak");
+	__builtin_unreachable();
 }
 
-//----------------------------------------------------------------------
-// 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++);
+		*(volatile int*)0x10000000 = *(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
+	// close is called before _exit()
 	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)
+int fstat(int file, struct stat *st)
 {
+	// fstat is called during libc startup
 	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
@@ -450,20 +83,13 @@ void *sbrk(ptrdiff_t incr)
 	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/syscalls.c b/scripts/cxxdemo/syscalls.c
index 16f791f..f12b07e 100644
--- a/scripts/cxxdemo/syscalls.c
+++ b/scripts/cxxdemo/syscalls.c
@@ -1,447 +1,80 @@
+// An extremely minimalist syscalls.c for newlib
 // 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
+// Written by Clifford Wolf.
 
 #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.
+#include <errno.h>
 
-off_t lseek(int file, off_t ptr, int dir)
-{
-	errno = ESPIPE;
-	return -1;
+#define UNIMPL_FUNC(_f) ".globl " #_f "\n.type " #_f ", @function\n" #_f ":\n"
+
+asm (
+	".text\n"
+	".align 2\n"
+	UNIMPL_FUNC(open)
+	UNIMPL_FUNC(openat)
+	UNIMPL_FUNC(lseek)
+	UNIMPL_FUNC(stat)
+	UNIMPL_FUNC(lstat)
+	UNIMPL_FUNC(fstatat)
+	UNIMPL_FUNC(isatty)
+	UNIMPL_FUNC(access)
+	UNIMPL_FUNC(faccessat)
+	UNIMPL_FUNC(link)
+	UNIMPL_FUNC(unlink)
+	UNIMPL_FUNC(execve)
+	UNIMPL_FUNC(getpid)
+	UNIMPL_FUNC(fork)
+	UNIMPL_FUNC(kill)
+	UNIMPL_FUNC(wait)
+	UNIMPL_FUNC(times)
+	UNIMPL_FUNC(gettimeofday)
+	UNIMPL_FUNC(ftime)
+	UNIMPL_FUNC(utime)
+	UNIMPL_FUNC(chown)
+	UNIMPL_FUNC(chmod)
+	UNIMPL_FUNC(chdir)
+	UNIMPL_FUNC(getcwd)
+	UNIMPL_FUNC(sysconf)
+	"j unimplemented_syscall\n"
+);
+
+void unimplemented_syscall()
+{
+	const char *p = "Unimplemented system call called!\n";
+	while (*p)
+		*(volatile int*)0x10000000 = *(p++);
+	asm volatile ("sbreak");
+	__builtin_unreachable();
 }
 
-//----------------------------------------------------------------------
-// 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++);
+		*(volatile int*)0x10000000 = *(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
+	// close is called before _exit()
 	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)
+int fstat(int file, struct stat *st)
 {
+	// fstat is called during libc startup
 	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
@@ -450,20 +83,13 @@ void *sbrk(ptrdiff_t incr)
 	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();
 }
+