seminaries/qtrvsim/os-emu-example: initial version of C library use example.

Functional in with user QEMU for 32 or even 64-bit build
on GNU{Linux system. printf() works on qtrvsim_gui but
actual malloc/sbrk code does not. qtrvsim_cli missing
system-calls support at all.

Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>

seminaries/qtrvsim/os-emu-example/.gitignore

+*.o
+*.srec
+depend
+malloc-test

seminaries/qtrvsim/os-emu-example/Makefile

+ARCH=riscv64-unknown-elf
+#ARCH=riscv64-linux-gnu
+
+SOURCES = malloc-test.c
+TARGET_EXE = malloc-test
+
+SOURCES += qtrvsim_sys_stub.c crt0local.S
+LOADLIBES += -lc
+
+CC=$(ARCH)-gcc
+CXX=$(ARCH)-g++
+AS=$(ARCH)-as
+LD=$(ARCH)-ld
+OBJCOPY=$(ARCH)-objcopy
+
+ARCHFLAGS += -mabi=ilp32
+ARCHFLAGS += -march=rv32im
+ARCHFLAGS += -fno-lto
+
+#ARCHFLAGS += -mabi=lp64
+#ARCHFLAGS += -march=rv64imac
+
+CFLAGS  += -ggdb -Os -Wall
+CXXFLAGS+= -ggdb -Os -Wall
+AFLAGS  += -ggdb
+LDFLAGS += -ggdb
+LDFLAGS += -nostartfiles
+LDFLAGS += -nostdlib
+LDFLAGS += -static
+#LDFLAGS += -specs=/opt/musl/riscv64-linux-gnu/lib/musl-gcc.specs
+
+LOADLIBES += -lgcc
+
+CFLAGS  += $(ARCHFLAGS)
+CXXFLAGS+= $(ARCHFLAGS)
+AFLAGS  += $(ARCHFLAGS)
+LDFLAGS += $(ARCHFLAGS)
+
+OBJECTS += $(filter %.o,$(SOURCES:%.S=%.o))
+OBJECTS += $(filter %.o,$(SOURCES:%.c=%.o))
+OBJECTS += $(filter %.o,$(SOURCES:%.cpp=%.o))
+
+all : default
+
+.PHONY : default clean dep all run_test
+
+%.o:%.S
+	$(CC) -D__ASSEMBLY__ $(AFLAGS) -c $< -o $@
+
+%.o:%.c
+	$(CC) $(CFLAGS) $(CPPFLAGS) -c $< -o $@
+
+%.o:%.cpp
+	$(CXX) $(CXXFLAGS) $(CPPFLAGS) -c $<
+
+%.s:%.c
+	$(CC) $(CFLAGS) $(CPPFLAGS) -S $< -o $@
+
+default : $(TARGET_EXE)
+#default : run_test
+
+$(TARGET_EXE) : $(OBJECTS)
+	$(CC) $(LDFLAGS) $^ $(LOADLIBES) -o $@
+
+dep: depend
+
+depend: $(SOURCES) $(glob *.h)
+	echo '# autogenerated dependencies' > depend
+ifneq ($(filter %.S,$(SOURCES)),)
+	$(CC)  -D__ASSEMBLY__ $(AFLAGS) -w -E -M $(filter %.S,$(SOURCES)) \
+	  >> depend
+endif
+ifneq ($(filter %.c,$(SOURCES)),)
+	$(CC) $(CFLAGS) $(CPPFLAGS) -w -E -M $(filter %.c,$(SOURCES)) \
+	  >> depend
+endif
+ifneq ($(filter %.cpp,$(SOURCES)),)
+	$(CXX) $(CXXFLAGS) $(CPPFLAGS) -w -E -M $(filter %.cpp,$(SOURCES)) \
+	  >> depend
+endif
+
+clean:
+	rm -f *.o *.a $(OBJECTS) $(TARGET_EXE) depend
+
+run_test: $(TARGET_EXE)
+	qtrvsim_cli --pipelined \
+		--dump-cycles $< \
+		--serout serial_port.out
+
+#		--serin serial_port.in \
+
+-include depend

seminaries/qtrvsim/os-emu-example/crt0local.S

+/* minimal replacement of crt0.o which is else provided by C library */
+
+.globl main
+.globl _start
+.globl __start
+.globl _heap_stack_start
+.globl _heap_stack_end
+
+.option norelax
+
+.text
+
+__start:
+_start:
+	.option push
+	.option norelax
+	la gp, __global_pointer$
+	.option pop
+	la      sp, _heap_stack_end
+	addi    a0, zero, 0
+	addi    a1, zero, 0
+	jal     main
+quit:
+	addi    a0, zero, 0
+	addi    a7, zero, 93  /* SYS_exit */
+	ecall
+
+loop:	ebreak
+        beq     zero, zero, loop
+
+.bss
+
+_heap_stack_start:
+	.skip   16384
+_heap_stack_end:
+
+.end _start

seminaries/qtrvsim/os-emu-example/malloc-test.c

+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#define CHUNK_COUNT 5
+
+static inline
+uint32_t fill_value(int chunk, int idx)
+{
+  return (chunk * 77) ^ idx * 55;
+}
+
+static inline
+size_t chunk_len(int chunk)
+{
+  return chunk * 137;
+}
+
+int main(void)
+{
+
+  uint32_t *chunks[CHUNK_COUNT];
+
+  printf("Starting malloc-test\n");
+
+  for (int chunk = 0; chunk < CHUNK_COUNT; chunk++) {
+    size_t len = chunk_len(chunk);
+    uint32_t *p = malloc(len * sizeof(uint32_t));
+    chunks[chunk] = p;
+    if (!p) {
+      printf("FAILED alloc of chunk %d, len %d\n", chunk, (int)len);
+      exit(1);
+    } else {
+      printf("Alloc of chunk %d, len %d address %p\n", chunk, (int)len, p);
+    }
+    while (len--) {
+      *(p++) = fill_value(chunk, len);
+    }
+  }
+
+  for (int chunk = 0; chunk < CHUNK_COUNT; chunk++) {
+    size_t len = chunk_len(chunk);
+    uint32_t *p = chunks[chunk];
+    while (len--) {
+      if (*(p++) != fill_value(chunk, len)) {
+        printf("FAILED chunk %d, data compare\n", chunk);
+        exit(1);
+      }
+    }
+    printf("Chunk %d check OK\n", chunk);
+  }
+
+  printf("Succeed malloc-test\n");
+
+  return 0;
+}

seminaries/qtrvsim/os-emu-example/qtrvsim_regs.h

+// ******************************************************************
+//  QtRvSim emulator https://github.com/cvut/qtrvsim support filees
+//
+//  qtrvsim_regs.h  - definition of the QtRvSim simulator peripherals
+//
+//  (C) Copyright 2019 - 2022 by Pavel Pisa
+//      e-mail:   pisa@cmp.felk.cvut.cz
+//      homepage: http://cmp.felk.cvut.cz/~pisa
+//      license:  any combination of GPL, LGPL, MPL or BSD licenses
+//
+// ******************************************************************
+
+#ifndef QTRVSIM_REGS_H
+#define QTRVSIM_REGS_H
+
+// Serial port/terminal registers
+// There is mirror of this region at address 0xffff0000
+// to match QtSpim and Mars emulators
+
+#define SERIAL_PORT_BASE,      0xffffc000 // base address of serial port region
+
+#define SERP_RX_ST_REG,        0xffffc000 // Receiver status register
+#define SERP_RX_ST_REG_o,          0x0000 // Offset of RX_ST_REG
+#define SERP_RX_ST_REG_READY_m,       0x1 // Data byte is ready to be read
+#define SERP_RX_ST_REG_IE_m,          0x2 // Enable Rx ready interrupt
+
+#define SERP_RX_DATA_REG,      0xffffc004 // Received data byte in 8 LSB bits
+#define SERP_RX_DATA_REG_o,        0x0004 // Offset of RX_DATA_REG
+
+#define SERP_TX_ST_REG,        0xffffc008 // Transmitter status register
+#define SERP_TX_ST_REG_o,          0x0008 // Offset of TX_ST_REG
+#define SERP_TX_ST_REG_READY_m,       0x1 // Transmitter can accept next byte
+#define SERP_TX_ST_REG_IE_m,          0x2 // Enable Tx ready interrupt
+
+#define SERP_TX_DATA_REG,      0xffffc00c // Write word to send 8 LSB bits to terminal
+#define SERP_TX_DATA_REG_o,        0x000c // Offset of TX_DATA_REG
+
+
+// Memory mapped peripheral for dial knobs input,
+// LED and RGB LEDs output designed to match
+// MZ_APO education Zynq based board developed
+// by Petr Porazil and Pavel Pisa at PiKRON.com company
+
+#define SPILED_REG_BASE       0xffffc100 // base of SPILED port region
+
+#define SPILED_REG_LED_LINE   0xffffc104 // 32 bit word mapped as output
+#define SPILED_REG_LED_LINE_o     0x0004 // Offset of the LED_LINE
+#define SPILED_REG_LED_RGB1   0xffffc110 // RGB LED 1 color components
+#define SPILED_REG_LED_RGB1_o     0x0010 // Offset of LED_RGB1
+#define SPILED_REG_LED_RGB2   0xffffc114 // RGB LED 2 color components
+#define SPILED_REG_LED_RGB2_o     0x0014 // Offset of LED_RGB2
+#define SPILED_REG_KNOBS_8BIT 0xffffc124 // Three 8 bit knob values
+#define SPILED_REG_KNOBS_8BIT_o   0x0024 // Offset of KNOBS_8BIT
+
+// The simple 16-bit per pixel (RGB565) frame-buffer
+// display size is 480 x 320 pixel
+// Pixel format RGB565 expect
+//   bits 11 .. 15 red component
+//   bits  5 .. 10 green component
+//   bits  0 ..  4 blue component
+#define LCD_FB_START          0xffe00000
+#define LCD_FB_END            0xffe4afff
+
+// Mapping of interrupts
+// Irq number   Cause/Status Bit   Source
+//  2 / HW0      10                Serial port ready to accept character to Tx
+//  3 / HW1      11                There is received character ready to be read
+//  7 / HW5      15                Counter reached value in Compare register
+
+
+#endif /*QTRVSIM_REGS_H*/

seminaries/qtrvsim/os-emu-example/qtrvsim_sys_stub.c

+/* Support files for GNU libc.  Files in the system namespace go here.
+   Files in the C namespace (ie those that do not start with an
+   underscore) go in .c.  */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/fcntl.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <time.h>
+#include <sys/time.h>
+#include <sys/times.h>
+#include <errno.h>
+#include <reent.h>
+#include "qtrvsim_unistd.h"
+
+#define UNUSED_PARAM(symbol) ((void)(symbol))
+
+/* Register name - works in collusion with the linker.  */
+register char * stack_ptr asm ("sp");
+
+
+int _read(int file, char *ptr, int len);
+int
+_read (int file,
+       char * ptr,
+       int len)
+{
+	register int __a7 asm("a7") = __NR_read;
+	register int __a0 asm("a0") = file;
+	register char * __a1 asm("a1") = ptr;
+	register int __a2 asm("a2") = len;
+	__asm__ volatile (
+	"ecall\n\t"
+	: "=r" (__a0)
+	: "r" (__a7), "r" (__a0), "r" (__a1), "r"(__a2)
+	: );
+	return __a0 < 0 ? -1: __a0;
+}
+
+int _write(int file, const char *ptr, int len);
+int
+_write (int    file,
+	const char * ptr,
+	int    len)
+{
+	register int __a7 asm("a7") = __NR_write;
+	register int __a0 asm("a0") = file;
+	register const char * __a1 asm("a1") = ptr;
+	register int __a2 asm("a2") = len;
+	__asm__ volatile (
+	"ecall\n\t"
+	: "=r" (__a0)
+	: "r" (__a7), "r" (__a0), "r" (__a1), "r"(__a2)
+	: );
+	return __a0 < 0 ? -1: __a0;
+}
+
+
+int
+_lseek (int file,
+	int pos,
+	int dir)
+{
+	UNUSED_PARAM(file);
+	UNUSED_PARAM(pos);
+	UNUSED_PARAM(dir);
+
+	return -1;
+}
+
+int _openat(int fd, const char *path, int flags,	...);
+int
+_openat (int fd, const char * path,
+       int          flags,
+       ...)
+{
+	register int __a7 asm("a7") = __NR_openat;
+	// use fd = -100 for normal open behaviour. Full openat not supported.
+	register int __a0 asm("a0") = fd;
+	register const char * __a1 asm("a1") = path;
+	register int __a2 asm("a2") = flags;
+	register int __a3 asm("a3");
+
+	if (flags & O_CREAT) {
+		va_list list;
+		va_start(list, flags);
+		__a3 = va_arg(list, int);
+		va_end(list);
+	}
+
+	__asm__ volatile (
+	"ecall\n\t"
+	: "=r" (__a0)
+	: "r" (__a7), "r" (__a0), "r" (__a1), "r"(__a2), "r"(__a3)
+	: );
+	return __a0 < 0 ? -1: __a0;
+}
+
+int _close(int file);
+int
+_close (int file)
+{
+	register int __a7 asm("a7") = __NR_close;
+	register int __a0 asm("a0") = file;
+	__asm__ volatile (
+	"ecall\n\t"
+	: "=r" (__a0)
+	: "r" (__a7), "r" (__a0)
+	: );
+	return __a0 < 0 ? -1: __a0;
+}
+
+void _exit(int n);
+void
+_exit (int n)
+{
+	register int __a7 asm("a7") = __NR_exit;
+	register int __a0 asm("a0") = n;
+
+	while(1) __asm__ volatile (
+	"ecall\n\t"
+	:
+	: "r" (__a7), "r" (__a0)
+	: );
+}
+
+void abort(void);
+void abort(void)
+{
+	while(1) __asm__ volatile (
+	"ebreak\n\t"
+	:
+	:
+	: );
+}
+
+int _kill(int n, int m);
+int
+_kill (int n, int m)
+{
+  UNUSED_PARAM(n);
+  UNUSED_PARAM(m);
+  return -1;
+}
+
+int _getpid(void);
+int
+_getpid (void)
+{
+  return 1;
+}
+
+
+void *_sbrk(ptrdiff_t incr);
+void *
+_sbrk (ptrdiff_t incr)
+{
+  extern char    _heap_stack_start;
+  static char   *heap_end;
+  char *        prev_heap_end;
+
+  incr=(incr+3) & ~3;
+
+  if (heap_end == NULL)
+    heap_end = & _heap_stack_start;
+
+  prev_heap_end = heap_end;
+
+  if ((heap_end + incr > stack_ptr) && (&_heap_stack_start < stack_ptr))
+    {
+      /* Some of the libstdc++-v3 tests rely upon detecting
+	 out of memory errors, so do not abort here.  */
+#if 1
+      extern void abort (void);
+
+      _write (1, "_sbrk: Heap and stack collision\n", 32);
+
+      abort ();
+#else
+      errno = ENOMEM;
+      return (caddr_t) -1;
+#endif
+    }
+
+  heap_end += incr;
+
+  return /*(caddr_t)*/ prev_heap_end;
+}
+
+int _fstat(int file, struct stat *st);
+int
+_fstat (int file, struct stat * st)
+{
+  UNUSED_PARAM(file);
+  UNUSED_PARAM(st);
+  return -1;
+}
+
+int _stat (const char *fname, struct stat *st);
+int _stat (const char *fname, struct stat *st)
+{
+  UNUSED_PARAM(fname);
+  UNUSED_PARAM(st);
+  return -1;
+}
+
+int _link(const char *path1, const char *path2);
+int
+_link (const char *path1,
+       const char *path2)
+{
+  UNUSED_PARAM(path1);
+  UNUSED_PARAM(path2);
+  return -1;
+}
+
+int _unlink(const char *path);
+int
+_unlink (const char *path)
+{
+  UNUSED_PARAM(path);
+  return -1;
+}
+
+void _raise(void);
+void
+_raise (void)
+{
+  return;
+}
+
+int _gettimeofday(struct timeval *tp, struct timezone *tzp);
+int
+_gettimeofday (struct timeval *tp,
+	       struct timezone *tzp)
+{
+
+  if(tp)
+    {
+      tp->tv_sec = 0;
+      tp->tv_usec = 0;
+    }
+  /* Return fixed data for the timezone.  */
+  if (tzp)
+    {
+      tzp->tz_minuteswest = 0;
+      tzp->tz_dsttime = 0;
+    }
+
+  return 0;
+}
+
+/* Return a clock that ticks at 100Hz.  */
+clock_t _times(struct tms *tp);
+clock_t
+_times (struct tms * tp)
+{
+  clock_t timeval = 0;
+
+  if (tp)
+    {
+      tp->tms_utime  = timeval;	/* user time */
+      tp->tms_stime  = 0;	/* system time */
+      tp->tms_cutime = 0;	/* user time, children */
+      tp->tms_cstime = 0;	/* system time, children */
+    }
+
+  return timeval;
+};
+
+
+int isatty(int fd);
+int
+isatty (int fd)
+{
+  UNUSED_PARAM(fd);
+  return 1;
+}
+
+int _system(const char *s);
+int
+_system (const char *s)
+{
+  UNUSED_PARAM(s);
+  return -1;
+}
+
+int _rename(const char *oldpath, const char *newpath);
+int
+_rename (const char * oldpath, const char * newpath)
+{
+  UNUSED_PARAM(oldpath);
+  UNUSED_PARAM(newpath);
+  return -1;
+}
+
+/* extern (.*) ([^ ]*) _PARAMS \(\(struct _reent \*(,*)(.*)\)\); */
+/* \1 \2 (struct _reent *\3\4) { return \2(\4);} */
+
+struct _reent;
+
+int _close_r(struct _reent *reent, int file)
+{ UNUSED_PARAM(reent); return _close(file);}
+/*
+  int _fcntl_r(struct _reent *, int, int, int)
+  { return _fcntl( int, int, int);}
+*/
+int _fstat_r(struct _reent *reent, int file, struct stat *st);
+int _fstat_r(struct _reent *reent, int file, struct stat *st)
+{ UNUSED_PARAM(reent); return _fstat(file, st);}
+
+int _getpid_r(struct _reent *reent);
+int _getpid_r(struct _reent *reent)
+{ UNUSED_PARAM(reent); return _getpid();}
+
+int _kill_r(struct _reent *reent, int n, int m);
+int _kill_r(struct _reent *reent, int n, int m)
+{ UNUSED_PARAM(reent); return _kill(n, m);}
+
+int _link_r(struct _reent *reent, const char *path1, const char *path2);
+int _link_r(struct _reent *reent, const char *path1, const char *path2)
+{ UNUSED_PARAM(reent); return _link(path1, path2);}
+
+_off_t _lseek_r(struct _reent *reent, int file, _off_t pos, int dir);
+_off_t _lseek_r(struct _reent *reent, int file, _off_t pos, int dir)
+{ UNUSED_PARAM(reent); return _lseek(file, pos, dir);}
+
+int _open_r(struct _reent *reent, const char *path, int flags, int opts);
+int _open_r(struct _reent *reent, const char *path, int flags, int opts)
+{ UNUSED_PARAM(reent); return _openat(-100, path, flags, opts);}
+
+int _openat_r(struct _reent *reent, int fd, const char *path, int flags, int opts);
+int _openat_r(struct _reent *reent, int fd, const char *path, int flags, int opts)
+{ UNUSED_PARAM(reent); return _openat(fd, path, flags, opts);}
+
+_ssize_t _read_r(struct _reent *reent, int file, void *ptr, size_t len);
+_ssize_t _read_r(struct _reent *reent, int file, void *ptr, size_t len)
+{ UNUSED_PARAM(reent); return _read(file, ptr, len);}
+
+void *_sbrk_r(struct _reent *reent, ptrdiff_t incr);
+void *_sbrk_r(struct _reent *reent, ptrdiff_t incr)
+{ UNUSED_PARAM(reent); return _sbrk(incr);}
+
+int _stat_r(struct _reent *reent, const char *path, struct stat *st);
+int _stat_r(struct _reent *reent, const char *path, struct stat *st)
+{ UNUSED_PARAM(reent); return _stat(path, st);}
+
+int _unlink_r(struct _reent *reent, const char *path);
+int _unlink_r(struct _reent *reent, const char *path)
+{ UNUSED_PARAM(reent); return _unlink(path);}
+
+_ssize_t _write_r(struct _reent *reent, int file, const void *ptr, size_t len);
+_ssize_t _write_r(struct _reent *reent, int file, const void *ptr, size_t len)
+{ UNUSED_PARAM(reent); return _write(file, ptr, len);}
+
+/* FIXME: TDK added dummy functions. Need to implement. */
+int _isatty(int fd);
+int _isatty(int fd)
+{
+  UNUSED_PARAM(fd);
+  return -1;
+}
+
+int _swistat(int fd, struct stat *st);
+int _swistat(int fd, struct stat *st)
+{
+  UNUSED_PARAM(fd);
+  UNUSED_PARAM(st);
+  return -1;
+}
+
+/* Return a clock that ticks at 100Hz.  */
+clock_t _clock(void);
+clock_t _clock(void)
+{
+  clock_t timeval=0;
+  return timeval;
+}
+
+int _swiclose(int fh);
+int _swiclose(int fh)
+{
+  UNUSED_PARAM(fh);
+  return -1;
+}
+
+int _swiopen(const char *path, int flags);
+int _swiopen(const char *path, int flags)
+{
+  UNUSED_PARAM(path);
+  UNUSED_PARAM(flags);
+  return -1;
+}
+
+int _swiwrite(int fh, char *ptr, int len);
+int _swiwrite(int fh, char *ptr, int len)
+{
+  UNUSED_PARAM(fh);
+  UNUSED_PARAM(ptr);
+  UNUSED_PARAM(len);
+  return -1;
+}
+
+int _swilseek(int fd, int ptr, int dir);
+int _swilseek(int fd, int ptr, int dir)
+{
+  UNUSED_PARAM(fd);
+  UNUSED_PARAM(ptr);
+  UNUSED_PARAM(dir);
+  return -1;
+}
+
+int _swiread(int fh, char *ptr,	int len);
+int _swiread(int fh, char *ptr,	int len)
+{
+  UNUSED_PARAM(fh);
+  UNUSED_PARAM(ptr);
+  UNUSED_PARAM(len);
+  return -1;
+}
+
+void initialise_monitor_handles(void);
+void initialise_monitor_handles(void)
+{
+}

seminaries/qtrvsim/os-emu-example/qtrvsim_unistd.h

+// ******************************************************************
+//  QtRvSim emulator https://github.com/cvut/qtrvsim support filees
+//
+//  qtrvsim_unistd.h  - definition of the QtRvSim syscall numbers
+//
+//  (C) Copyright 2019 - 2022 by Pavel Pisa
+//      e-mail:   pisa@cmp.felk.cvut.cz
+//      homepage: http://cmp.felk.cvut.cz/~pisa
+//      license:  any combination of GPL, LGPL, MPL or BSD licenses
+//
+// ******************************************************************
+
+#ifndef QTRVSIM_UNISTD_H
+#define QTRVSIM_UNISTD_H
+
+// Linux kernel compatible system calls subset
+
+#define __NR_exit         93  // void exit(int status)
+#define __NR_read         63  // ssize_t read(int fd, void *buf, size_t count)
+#define __NR_write        64  // ssize_t write(int fd, const void *buf, size_t count)
+#define __NR_close        57  // int close(int fd)
+#define __NR_openat       56  // int openat(int fd, const char *pathname, int flags, mode_t mode)
+        // use fd = -100 for normal open behaviour. Full openat not supported.
+#define __NR_brk         214 // void * brk(void *addr)
+#define __NR_ftruncate64  46  // int ftruncate64(int fd, off_t length)
+#define __NR_readv        65  // ssize_t readv(int fd, const struct iovec *iov, int iovcnt)
+#define __NR_writev       66  // ssize_t writev(int fd, const struct iovec *iov, int iovcnt)
+
+#endif /*QTRVSIM_UNISTD_H*/