diff --git a/seminaries/hello-apo/.gitingnore b/seminaries/hello-apo/.gitingnore
new file mode 100644
index 0000000000000000000000000000000000000000..2fe532e90ea841795e63cbcc4314e63e6accb079
--- /dev/null
+++ b/seminaries/hello-apo/.gitingnore
@@ -0,0 +1,9 @@
+*.o
+*.dump
+*-native
+*-x86
+*-riscv
+*-riscv64
+*-mips
+*-arm
+*-aarch64
diff --git a/seminaries/hello-apo/Makefile b/seminaries/hello-apo/Makefile
new file mode 100644
index 0000000000000000000000000000000000000000..a123f1fbfe048d437d4bb72ca92a83cdc13ac775
--- /dev/null
+++ b/seminaries/hello-apo/Makefile
@@ -0,0 +1,109 @@
+# Makefile to buidl example for different ISA targets
+# Select architecture by ARCH parameter
+# native, x86, riscv, riscv64, mips, arm, aarch64
+
+# Specify source files of the program
+SOURCES = hello-apo.c
+
+# Specify base name of the executable - architecture
+TARGET_BASE = hello-apo
+
+# The actual target filename is unique for each architecture
+TARGET_EXE = $(TARGET_BASE)-$(ARCH)
+
+all: default
+
+.PHONY : all default build run dump clean
+
+ARCH_SUPPORTED = native x86 riscv riscv64 mips arm aarch64
+
+ifneq ($(MAKECMDGOALS),clean)
+ifeq ($(filter $(ARCH_SUPPORTED),$(ARCH)),)
+ $(error ARCH parameter has to be set accepted: x86, riscv, riscv64, mips and arm)
+endif
+endif
+
+# setting specific for riscv build for native build
+SOURCES-native +=
+LOADLIBES-native +=
+CC-native = gcc
+OBJDUMP-native = objdump
+ARCHFLAGS-native += -ggdb
+RUN-native =
+
+# setting specific for riscv build for native build
+SOURCES-x86 +=
+LOADLIBES-x86 +=
+CC-x86 = x86_64-linux-gnu-gcc
+OBJDUMP-x86 = x86_64-linux-gnu-objdump
+ARCHFLAGS-native += -static -ggdb
+RUN-x86 = qemu-x86_64-static
+
+# setting specific for riscv build for QtRvSim simulator and or RISC-V Linux 32-bit run
+SOURCES-riscv += sys-qtrvsim/qtrvsim_sys_stub.c sys-qtrvsim/crt0local.S
+LOADLIBES-riscv += -lc -lgcc
+CC-riscv = riscv64-unknown-elf-gcc
+OBJDUMP-riscv = riscv64-unknown-elf-objdump
+ARCHFLAGS-riscv += -mabi=ilp32 -march=rv32im -fno-lto -nostartfiles -nostdlib -static -ggdb
+RUN-riscv = qemu-riscv32-static
+
+# setting specific for riscv64 build for QtRvSim simulator and or RISC-V Linux 64-bit run
+SOURCES-riscv64 += sys-qtrvsim/qtrvsim_sys_stub.c sys-qtrvsim/crt0local.S
+LOADLIBES-riscv64 += -lc -lgcc
+CC-riscv64 = riscv64-unknown-elf-gcc
+OBJDUMP-riscv64 = riscv64-unknown-elf-objdump
+ARCHFLAGS-riscv64 += -mabi=lp64 -march=rv64imac -fno-lto -nostartfiles -nostdlib -static -ggdb
+RUN-riscv64 = qemu-riscv64-static
+
+# setting specific for riscv64 build for QtMips simulator and or MIPS Linux run
+SOURCES-mips += sys-qtmips/qtmips_sys_stub.c sys-qtmips/crt0local.S
+LOADLIBES-mips += -lc -lgcc
+CC-mips = mips-elf-gcc
+OBJDUMP-mips = mips-elf-objdump
+ARCHFLAGS-mips += -march=mips32 -fno-lto -nostartfiles -nostdlib -static -ggdb
+RUN-mips = qemu-mips-static
+
+# setting specific for ARM 32-bit build
+SOURCES-arm +=
+LOADLIBES-arm +=
+CC-arm = arm-linux-gnueabihf-gcc
+OBJDUMP-arm = arm-linux-gnueabihf-objdump
+ARCHFLAGS-arm += -static -ggdb
+RUN-arm = qemu-arm-static
+
+# setting specific for ARM 64-bit build
+SOURCES-aarch64 +=
+LOADLIBES-aarch64 +=
+CC-aarch64 = aarch64-linux-gnu-gcc
+OBJDUMP-aarch64 = aarch64-linux-gnu-objdump
+ARCHFLAGS-aarch64 += -static -ggdb
+RUN-aarch64 = qemu-aarch64-static
+
+define compile_one_src
+src := $(1)
+arch := $(2)
+obj := $$(basename $$(notdir $$(src)))-$$(arch).o
+$$(obj) : $$(src)
+ $$(CC-$$(arch)) $$(ARCHFLAGS-$$(arch)) -c $$< -o $$@
+OBJS-$$(arch) := $$(OBJS-$$(arch)) $$(obj)
+#$$(warning $$(src) $$(obj) $$(arch) $$(OBJS-$$(arch)))
+endef
+
+$(foreach srci, $(SOURCES) $(SOURCES-$(ARCH)),$(eval $(call compile_one_src, $(srci), $(ARCH))))
+
+$(TARGET_EXE) : $(OBJS-$(ARCH))
+ $(CC-$(ARCH)) -o $@ $^ $(ARCHFLAGS-$(ARCH)) $(LOADLIBES-$(ARCH))
+
+build : $(TARGET_EXE)
+
+run : $(TARGET_EXE)
+ $(RUN-$(ARCH)) ./$<
+
+dump: $(TARGET_EXE)
+ $(OBJDUMP-$(ARCH)) --source $< > $<.dump
+ cat $<.dump
+
+clean :
+ rm -f $(OBJS-$(ARCH)) $(foreach arch,$(ARCH_SUPPORTED),$(TARGET_BASE)-$(arch)) *.o *.dump
+
+default : build
\ No newline at end of file
diff --git a/seminaries/hello-apo/hello-apo.c b/seminaries/hello-apo/hello-apo.c
new file mode 100644
index 0000000000000000000000000000000000000000..b6197a548067d21239bafdfe27f4b167d9bc4134
--- /dev/null
+++ b/seminaries/hello-apo/hello-apo.c
@@ -0,0 +1,25 @@
+/* Hello world example to demonstrate on multiple architectures */
+
+/*
+ * compile, run and examine for different instruction set architectures
+ * build by make command where ARCH is chisen as one of
+ * native, x86, riscv, riscv64, mips, arm or aarch64
+ * make ARCH=riscv
+ */
+
+#include <stdio.h>
+
+//int var_a = 40;
+//int var_b = 2;
+
+int main(int argc, char *argv[])
+{
+
+ /*
+ * modify program to compute and print answer
+ * of var_a + var_b
+ */
+ printf("Hello APO\n");
+
+ return 0;
+}
diff --git a/seminaries/hello-apo/sys-qtmips/crt0local.S b/seminaries/hello-apo/sys-qtmips/crt0local.S
new file mode 100644
index 0000000000000000000000000000000000000000..1931e765e4915b95bee4ee22ca4096795f2700e9
--- /dev/null
+++ b/seminaries/hello-apo/sys-qtmips/crt0local.S
@@ -0,0 +1,47 @@
+/* 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
+.set noat
+.set noreorder
+.ent _start
+
+.text
+
+__start:
+_start:
+#if defined(__PIC__) || defined(__pic__)
+ bal next
+ nop
+next:
+ .set noreorder
+ .cpload $31
+ .set reorder
+#else
+ la $gp, _gp
+#endif
+ la $sp, _heap_stack_end
+ addi $a0, $zero, 0
+ addi $a1, $zero, 0
+ jal main
+ nop
+quit:
+ addi $a0, $zero, 0
+ addi $v0, $zero, 4001 /* SYS_exit */
+
+ syscall
+
+loop: break
+ beq $zero, $zero, loop
+ nop
+
+.end _start
+
+.bss
+
+_heap_stack_start:
+ .skip 0x800000
+_heap_stack_end:
diff --git a/seminaries/hello-apo/sys-qtmips/qtmips_sys_stub.c b/seminaries/hello-apo/sys-qtmips/qtmips_sys_stub.c
new file mode 100644
index 0000000000000000000000000000000000000000..119f5d3613816ba5783a82766f3e4a7b78e4efd8
--- /dev/null
+++ b/seminaries/hello-apo/sys-qtmips/qtmips_sys_stub.c
@@ -0,0 +1,436 @@
+/* Support files for GNU libc. Files in the system namespace go here.
+ Files in the C namespace (ie those that do not start with an
+ underscore) go in .c. */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/fcntl.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <time.h>
+#include <sys/time.h>
+#include <sys/times.h>
+#include <errno.h>
+#include <reent.h>
+#include "qtmips_unistd.h"
+
+#define UNUSED_PARAM(symbol) ((void)(symbol))
+
+/* Register name - works in collusion with the linker. */
+register char * stack_ptr asm ("sp");
+
+
+int _read(int file, char *ptr, int len);
+int
+_read (int file,
+ char * ptr,
+ int len)
+{
+ register int __v0 asm("$v0") = __NR_read;
+ register int __a0 asm("$a0") = file;
+ register char * __a1 asm("$a1") = ptr;
+ register int __a2 asm("$a2") = len;
+ register int __a3 asm("$a3");
+ __asm__ volatile (
+ ".set\tnoreorder\n\t"
+ "syscall\n\t"
+ ".set reorder"
+ : "=r" (__v0), "=r" (__a3)
+ : "r" (__v0), "r" (__a0), "r" (__a1), "r"(__a2)
+ : );
+ return __a3? -1: __v0;
+}
+
+int _write(int file, const char *ptr, int len);
+int
+_write (int file,
+ const char * ptr,
+ int len)
+{
+ register int __v0 asm("$v0") = __NR_write;
+ register int __a0 asm("$a0") = file;
+ register const char * __a1 asm("$a1") = ptr;
+ register int __a2 asm("$a2") = len;
+ register int __a3 asm("$a3");
+ __asm__ volatile (
+ ".set\tnoreorder\n\t"
+ "syscall\n\t"
+ ".set reorder"
+ : "=r" (__v0), "=r" (__a3)
+ : "r" (__v0), "r" (__a0), "r" (__a1), "r"(__a2)
+ : );
+ return __a3? -1: __v0;
+}
+
+
+int
+_lseek (int file,
+ int pos,
+ int dir)
+{
+ UNUSED_PARAM(file);
+ UNUSED_PARAM(pos);
+ UNUSED_PARAM(dir);
+
+ return -1;
+}
+
+int _open(const char *path, int flags, ...);
+int
+_open (const char * path,
+ int flags,
+ ...)
+{
+ register int __v0 asm("$v0") = __NR_open;
+ register const char * __a0 asm("$a0") = path;
+ register int __a1 asm("$a1") = flags;
+ register int __a2 asm("$a2") = 0;
+ register int __a3 asm("$a3");
+
+ if (flags & O_CREAT) {
+ va_list list;
+ va_start(list, flags);
+ __a2 = va_arg(list, int);
+ va_end(list);
+ }
+
+ __asm__ volatile (
+ ".set\tnoreorder\n\t"
+ "syscall\n\t"
+ ".set reorder"
+ : "=r" (__v0), "=r" (__a3)
+ : "r" (__v0), "r" (__a0), "r" (__a1), "r"(__a2)
+ : );
+ return __a3? -1: __v0;
+}
+
+int _close(int file);
+int
+_close (int file)
+{
+ register int __v0 asm("$v0") = __NR_close;
+ register int __a0 asm("$a0") = file;
+ register int __a3 asm("$a3");
+ __asm__ volatile (
+ ".set\tnoreorder\n\t"
+ "syscall\n\t"
+ ".set reorder"
+ : "=r" (__v0), "=r" (__a3)
+ : "r" (__v0), "r" (__a0)
+ : );
+ return __a3? -1: __v0;
+}
+
+void _exit(int n);
+void
+_exit (int n)
+{
+ register int __v0 asm("$v0") = __NR_exit;
+ register int __a0 asm("$a0") = n;
+
+ while(1) __asm__ volatile (
+ ".set\tnoreorder\n\t"
+ "syscall\n\t"
+ ".set reorder"
+ :
+ : "r" (__v0), "r" (__a0)
+ : "a3");
+}
+
+void abort(void);
+void abort(void)
+{
+ while(1) __asm__ volatile (
+ ".set\tnoreorder\n\t"
+ "break\n\t"
+ ".set reorder"
+ :
+ :
+ : );
+}
+
+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 _open(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)
+{
+}
diff --git a/seminaries/hello-apo/sys-qtmips/qtmips_unistd.h b/seminaries/hello-apo/sys-qtmips/qtmips_unistd.h
new file mode 100644
index 0000000000000000000000000000000000000000..e1a686967c708635189ed60a4f7bee8252a9d211
--- /dev/null
+++ b/seminaries/hello-apo/sys-qtmips/qtmips_unistd.h
@@ -0,0 +1,29 @@
+// ******************************************************************
+// QtMips emulator https://github.com/cvut/QtMips support filees
+//
+// qtmips_unistd.h - definition of the QtMips syscall numbers
+//
+// (C) Copyright 2019 - 2020 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 QTMIPS_UNISTD_H
+#define QTMIPS_UNISTD_H
+
+// Linux kernel compatible system calls subset
+
+#define __NR_exit 4001 // void exit(int status)
+#define __NR_read 4003 // ssize_t read(int fd, void *buf, size_t count)
+#define __NR_write 4004 // ssize_t write(int fd, const void *buf, size_t count)
+#define __NR_close 4006 // int close(int fd)
+#define __NR_open 4005 // int open(const char *pathname, int flags, mode_t mode)
+#define __NR_brk 4045 // void * brk(void *addr)
+#define __NR_truncate 4092 // int ftruncate(int fd, off_t length)
+#define __NR_readv 4145 // ssize_t readv(int fd, const struct iovec *iov, int iovcnt)
+#define __NR_writev 4146 // ssize_t writev(int fd, const struct iovec *iov, int iovcnt)
+#define __NR_set_thread_area 4283 // int set_thread_area(unsigned long addr)
+
+#endif /*QTMIPS_UNISTD_H*/
diff --git a/seminaries/hello-apo/sys-qtrvsim/crt0local.S b/seminaries/hello-apo/sys-qtrvsim/crt0local.S
new file mode 100644
index 0000000000000000000000000000000000000000..20017869ebfd71380908cd2aea560595e8d9b698
--- /dev/null
+++ b/seminaries/hello-apo/sys-qtrvsim/crt0local.S
@@ -0,0 +1,37 @@
+/* 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
diff --git a/seminaries/hello-apo/sys-qtrvsim/qtrvsim_sys_stub.c b/seminaries/hello-apo/sys-qtrvsim/qtrvsim_sys_stub.c
new file mode 100644
index 0000000000000000000000000000000000000000..e56603e3a90ac37555e4c82e307ac4ffa9b749f4
--- /dev/null
+++ b/seminaries/hello-apo/sys-qtrvsim/qtrvsim_sys_stub.c
@@ -0,0 +1,502 @@
+/* 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))
+
+
+/* Open flags definition for Linux kernel copied from musl-libc */
+
+#define KERNEL_O_CREAT 0100
+#define KERNEL_O_EXCL 0200
+#define KERNEL_O_NOCTTY 0400
+#define KERNEL_O_TRUNC 01000
+#define KERNEL_O_APPEND 02000
+#define KERNEL_O_NONBLOCK 04000
+#define KERNEL_O_DSYNC 010000
+#define KERNEL_O_SYNC 04010000
+#define KERNEL_O_RSYNC 04010000
+#define KERNEL_O_DIRECTORY 0200000
+#define KERNEL_O_NOFOLLOW 0400000
+#define KERNEL_O_CLOEXEC 02000000
+
+#define KERNEL_O_PATH 010000000
+
+#define KERNEL_O_SYNC1 040000
+
+#define KERNEL_O_ACCMODE (03 | KERNEL_O_PATH)
+#define KERNEL_O_RDONLY 00
+#define KERNEL_O_WRONLY 01
+#define KERNEL_O_RDWR 02
+
+#define TARGET_AT_FDCWD -100
+
+/* 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") = 0;
+ register int __a3 asm("a3");
+
+#ifdef O_CREAT
+ if (flags & O_CREAT)
+ __a2 |= KERNEL_O_CREAT;
+#endif
+#ifdef O_EXCL
+ if (flags & O_EXCL)
+ __a2 |= KERNEL_O_EXCL;
+#endif
+#ifdef O_NOCTTY
+ if (flags & O_NOCTTY)
+ __a2 |= KERNEL_O_NOCTTY;
+#endif
+#ifdef O_TRUNC
+ if (flags & O_TRUNC)
+ __a2 |= KERNEL_O_TRUNC;
+#endif
+#ifdef O_APPEND
+ if (flags & O_APPEND)
+ __a2 |= KERNEL_O_APPEND;
+#endif
+#ifdef O_NONBLOCK
+ if (flags & O_NONBLOCK)
+ __a2 |= KERNEL_O_NONBLOCK;
+#endif
+#ifdef O_DSYNC
+ if (flags & O_DSYNC)
+ __a2 |= KERNEL_O_DSYNC;
+#endif
+#ifdef O_SYNC
+ if (flags & O_SYNC)
+ __a2 |= KERNEL_O_SYNC;
+#endif
+#ifdef O_RSYNC
+ if (flags & O_RSYNC)
+ __a2 |= KERNEL_O_RSYNC;
+#endif
+#ifdef O_DIRECTORY
+ if (flags & O_DIRECTORY)
+ __a2 |= KERNEL_O_DIRECTORY;
+#endif
+#ifdef O_NOFOLLOW
+ if (flags & O_NOFOLLOW)
+ __a2 |= KERNEL_O_NOFOLLOW;
+#endif
+#ifdef O_CLOEXEC
+ if (flags & O_CLOEXEC)
+ __a2 |= KERNEL_O_CLOEXEC;
+#endif
+
+ 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(TARGET_AT_FDCWD, 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)
+{
+}
diff --git a/seminaries/hello-apo/sys-qtrvsim/qtrvsim_unistd.h b/seminaries/hello-apo/sys-qtrvsim/qtrvsim_unistd.h
new file mode 100644
index 0000000000000000000000000000000000000000..219d676f13d3b58ab04ddd2c005dced918a07de3
--- /dev/null
+++ b/seminaries/hello-apo/sys-qtrvsim/qtrvsim_unistd.h
@@ -0,0 +1,29 @@
+// ******************************************************************
+// 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*/