demo: implement remote cmds

1 files changed, 31 insertions, 0 deletions

diff --git a/demo/mem.c b/demo/mem.c
new file mode 100644
index 0000000..2551385
--- /dev/null
+++ b/demo/mem.c
@@ -0,0 +1,31 @@
+#include "demo.h"
+
+void do_read(void *ptr)
+{
+	print("%p -> %x", ptr, *(volatile unsigned *)ptr);
+}
+
+void do_write(void *ptr, unsigned val)
+{
+	*(volatile unsigned *)ptr = val;
+	print("%p <- %x", ptr, val);
+}
+
+void remote_send(unsigned cpu, void *ptr, int write, unsigned val)
+{
+	unsigned long ptr_val = (unsigned)ptr & ~0b11;
+	unsigned long long send_word = ((unsigned long long)ptr_val | (write & 1) << 1 | 1) << 32 | val;
+
+	unsigned long long current = all_cpus[cpu].mailbox;
+	while (!compare_exchange_64(&all_cpus[cpu].mailbox, &current, send_word));
+}
+
+void remote_recv(void **ptr, int *write, unsigned *val)
+{
+	unsigned long long current = this_cpu->mailbox;
+	while (!compare_exchange_64(&this_cpu->mailbox, &current, 0) || !current);
+
+	*val = (unsigned long)current;
+	*ptr = (void *)((unsigned)((current >> 32) & ~0b11));
+	*write = (current >> 33) & 1;
+}