(libco) Add aarch64 backend

libretro-common/libco/aarch64.c

@@ -0,0 +1,129 @@
+/*
+  libco.aarch64 (2017-06-26)
+  author: webgeek1234
+  license: public domain
+*/
+
+#define LIBCO_C
+#include "libco.h"
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+
+#ifndef IOS
+#include <malloc.h>
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+static thread_local uint64_t co_active_buffer[64];
+static thread_local cothread_t co_active_handle;
+
+asm (
+      ".globl co_switch_aarch64\n"
+      ".globl _co_switch_aarch64\n"
+      "co_switch_aarch64:\n"
+      "_co_switch_aarch64:\n"
+      "  stp x8,  x9,  [x1]\n"
+      "  stp x10, x11, [x1, #16]\n"
+      "  stp x12, x13, [x1, #32]\n"
+      "  stp x14, x15, [x1, #48]\n"
+      "  str x19, [x1, #72]\n"
+      "  stp x20, x21, [x1, #80]\n"
+      "  stp x22, x23, [x1, #96]\n"
+      "  stp x24, x25, [x1, #112]\n"
+      "  stp x26, x27, [x1, #128]\n"
+      "  stp x28, x29, [x1, #144]\n"
+      "  mov x16, sp\n"
+      "  stp x16, x30, [x1, #160]\n"
+
+      "  ldp x8,  x9,  [x0]\n"
+      "  ldp x10, x11, [x0, #16]\n"
+      "  ldp x12, x13, [x0, #32]\n"
+      "  ldp x14, x15, [x0, #48]\n"
+      "  ldr x19, [x0, #72]\n"
+      "  ldp x20, x21, [x0, #80]\n"
+      "  ldp x22, x23, [x0, #96]\n"
+      "  ldp x24, x25, [x0, #112]\n"
+      "  ldp x26, x27, [x0, #128]\n"
+      "  ldp x28, x29, [x0, #144]\n"
+      "  ldp x16, x17, [x0, #160]\n"
+      "  mov sp, x16\n"
+      "  br x17\n"
+    );
+
+/* ASM */
+void co_switch_aarch64(cothread_t handle, cothread_t current);
+
+static void crash(void)
+{
+   /* Called only if cothread_t entrypoint returns. */
+   assert(0);
+}
+
+cothread_t co_create(unsigned int size, void (*entrypoint)(void))
+{
+   size = (size + 1023) & ~1023;
+   cothread_t handle = 0;
+#if HAVE_POSIX_MEMALIGN >= 1
+   if (posix_memalign(&handle, 1024, size + 512) < 0)
+      return 0;
+#else
+   handle = memalign(1024, size + 512);
+#endif
+
+   if (!handle)
+      return handle;
+
+   uint64_t *ptr = (uint64_t*)handle;
+   /* Non-volatiles.  */
+   ptr[0]  = 0; /* x8  */
+   ptr[1]  = 0; /* x9  */
+   ptr[2]  = 0; /* x10 */
+   ptr[3]  = 0; /* x11 */
+   ptr[4]  = 0; /* x12 */
+   ptr[5]  = 0; /* x13 */
+   ptr[6]  = 0; /* x14 */
+   ptr[7]  = 0; /* x15 */
+   ptr[8]  = 0; /* padding */
+   ptr[9]  = 0; /* x19 */
+   ptr[10] = 0; /* x20 */
+   ptr[11] = 0; /* x21 */
+   ptr[12] = 0; /* x22 */
+   ptr[13] = 0; /* x23 */
+   ptr[14] = 0; /* x24 */
+   ptr[15] = 0; /* x25 */
+   ptr[16] = 0; /* x26 */
+   ptr[17] = 0; /* x27 */
+   ptr[18] = 0; /* x28 */
+   ptr[20] = (uintptr_t)ptr + size + 512 - 16; /* x30, stack pointer */
+   ptr[19] = ptr[20]; /* x29, frame pointer */
+   ptr[21] = (uintptr_t)entrypoint; /* PC (link register x31 gets saved here). */
+   return handle;
+}
+
+cothread_t co_active(void)
+{
+   if (!co_active_handle)
+      co_active_handle = co_active_buffer;
+   return co_active_handle;
+}
+
+void co_delete(cothread_t handle)
+{
+   free(handle);
+}
+
+void co_switch(cothread_t handle)
+{
+   cothread_t co_previous_handle = co_active();
+   co_switch_aarch64(co_active_handle = handle, co_previous_handle);
+}
+
+#ifdef __cplusplus
+}
+#endif
+

libretro-common/libco/libco.c

@@ -22,6 +22,8 @@
     #include "amd64.c"
   #elif defined _ARCH_PPC
     #include "ppc.c"
+  #elif defined(__aarch64__)
+    #include "aarch64.c"
   #elif defined VITA
     #include "scefiber.c"
   #elif defined(__ARM_EABI__) || defined(__arm__)