From dd8dfa32f8592bab0c3aa2b326deae16dd9a5c73 Mon Sep 17 00:00:00 2001
From: Alexandru RADOVICI <alexandru.radovici@wyliodrin.com>
Date: Tue, 12 Jul 2022 10:14:45 +0300
Subject: [PATCH 1/2] packed syscalls example

---
 examples/packed/Makefile  | 11 ++++++
 examples/packed/README.md |  8 +++++
 examples/packed/main.c    | 76 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 95 insertions(+)
 create mode 100644 examples/packed/Makefile
 create mode 100644 examples/packed/README.md
 create mode 100644 examples/packed/main.c

diff --git a/examples/packed/Makefile b/examples/packed/Makefile
new file mode 100644
index 000000000..cfe30ad8e
--- /dev/null
+++ b/examples/packed/Makefile
@@ -0,0 +1,11 @@
+# Makefile for user application
+
+# Specify this directory relative to the current application.
+TOCK_USERLAND_BASE_DIR = ../..
+
+# Which files to compile.
+C_SRCS := $(wildcard *.c)
+
+# Include userland master makefile. Contains rules and flags for actually
+# building the application.
+include $(TOCK_USERLAND_BASE_DIR)/AppMakefile.mk
diff --git a/examples/packed/README.md b/examples/packed/README.md
new file mode 100644
index 000000000..8992863b5
--- /dev/null
+++ b/examples/packed/README.md
@@ -0,0 +1,8 @@
+Blink App
+=========
+
+The canonical "blink" app for an embedded platform. This app will
+blink all of the LEDs that are registered with the kernel.
+
+To learn more, please see the
+[Blink an LED](../../../doc/tutorials/01_running_blink.md) tutorial.
diff --git a/examples/packed/main.c b/examples/packed/main.c
new file mode 100644
index 000000000..8acefa9b2
--- /dev/null
+++ b/examples/packed/main.c
@@ -0,0 +1,76 @@
+#include <led.h>
+#include <timer.h>
+
+#if defined(__thumb__)
+static syscall_return_t packed(uint32_t count, uint32_t *data,
+                         bool stop_error) {
+  register uint32_t r0 __asm__ ("r0") = count;
+  register uint32_t *r1 __asm__ ("r1") = data;
+  register uint32_t r2 __asm__ ("r2") = stop_error;
+  register uint32_t r3 __asm__ ("r3") = 0;
+  register uint32_t rtype __asm__ ("r0");
+  register uint32_t rv1 __asm__ ("r1");
+  register uint32_t rv2 __asm__ ("r2");
+  register uint32_t rv3 __asm__ ("r3");
+  __asm__ volatile (
+    "svc 0xfe"
+    : "=r" (rtype), "=r" (rv1), "=r" (rv2), "=r" (rv3)
+    : "r" (r0), "r" (r1), "r" (r2), "r" (r3)
+    : "memory"
+    );
+  syscall_return_t rval = {rtype, {rv1, rv2, rv3}};
+  return rval;
+}
+#elif defined(__riscv)
+static syscall_return_t packed(uint32_t count, uint32_t *data,
+                         bool stop_error) {
+  register uint32_t a0  __asm__ ("a0") = count;
+  register uint32_t *a1  __asm__ ("a1") = data;
+  register uint32_t a2  __asm__ ("a2") = stop_error;
+  register uint32_t a3  __asm__ ("a3") = 0;
+  register uint32_t a4  __asm__ ("a4") = 0xfe;
+  register int rtype __asm__ ("a0");
+  register int rv1 __asm__ ("a1");
+  register int rv2 __asm__ ("a2");
+  register int rv3 __asm__ ("a3");
+  __asm__ volatile (
+    "ecall\n"
+    : "=r" (rtype), "=r" (rv1), "=r" (rv2), "=r" (rv3)
+    : "r" (a0), "r" (a1), "r" (a2), "r" (a3), "r" (a4)
+    : "memory");
+  syscall_return_t rval = {rtype, {rv1, rv2, rv3}};
+  return rval;
+}
+#endif
+
+int main(void) {
+
+    uint32_t data[25*5];
+
+    bool light = true;
+
+    while (true) {
+
+    for (int i=0; i < 25; i++) {
+      data[0 + 5*i] = 2;
+      data[1 + 5*i] = 4;
+      data[2 + 5*i] = (light?2:3);
+      data[3 + 5*i] = i;
+      data[4 + 5*i] = 0;
+    }
+    syscall_return_t res = packed(25, data, true);
+
+    if (res.type == TOCK_SYSCALL_FAILURE_U32) {
+      printf ("Executed %ld syscalls\n", 25 - res.data[0]); 
+    }
+
+    light = !light;
+
+    for (int i = 0; i < 25; i++) {
+      printf ("syscall %d res %ld\n", i, data[1 + 5*i]);
+    }
+
+    // This delay uses an underlying timer in the kernel.
+    delay_ms(250);
+  }
+}

From b45b8df68a3dc0affb1a24f61bad4099fbc31a8a Mon Sep 17 00:00:00 2001
From: Alexandru RADOVICI <alexandru.radovici@wyliodrin.com>
Date: Tue, 12 Jul 2022 10:19:17 +0300
Subject: [PATCH 2/2] display syscalls errors

---
 examples/packed/main.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/examples/packed/main.c b/examples/packed/main.c
index 8acefa9b2..857be9f7d 100644
--- a/examples/packed/main.c
+++ b/examples/packed/main.c
@@ -60,13 +60,16 @@ int main(void) {
     }
     syscall_return_t res = packed(25, data, true);
 
+    int executed_syscalls = 25;
+
     if (res.type == TOCK_SYSCALL_FAILURE_U32) {
       printf ("Executed %ld syscalls\n", 25 - res.data[0]); 
+      executed_syscalls = 25 - res.data[0];
     }
 
     light = !light;
 
-    for (int i = 0; i < 25; i++) {
+    for (int i = 0; i < executed_syscalls; i++) {
       printf ("syscall %d res %ld\n", i, data[1 + 5*i]);
     }