1 files changed, 67 insertions, 0 deletions
diff --git a/tinycc/lib/va_list.c b/tinycc/lib/va_list.c
new file mode 100644
index 0000000..1fb5512
--- /dev/null
+++ b/tinycc/lib/va_list.c
@@ -0,0 +1,67 @@
+/* va_list.c - tinycc support for va_list on X86_64 */
+
+#if defined __x86_64__
+
+/* Avoid include files, they may not be available when cross compiling */
+extern void abort(void);
+
+/* This should be in sync with our include/stdarg.h */
+enum __va_arg_type {
+    __va_gen_reg, __va_float_reg, __va_stack
+};
+
+/* GCC compatible definition of va_list. */
+/*predefined by TCC (tcc_predefs.h):
+typedef struct {
+    unsigned int gp_offset;
+    unsigned int fp_offset;
+    union {
+        unsigned int overflow_offset;
+        char *overflow_arg_area;
+    };
+    char *reg_save_area;
+} __builtin_va_list[1];
+*/
+
+extern void *memcpy(void *dest, const void *src, unsigned long n);
+
+void *__va_arg(__builtin_va_list ap,
+               int arg_type,
+               int size, int align)
+{
+    size = (size + 7) & ~7;
+    align = (align + 7) & ~7;
+    switch ((enum __va_arg_type)arg_type) {
+    case __va_gen_reg:
+        if (ap->gp_offset + size <= 48) {
+            ap->gp_offset += size;
+            return ap->reg_save_area + ap->gp_offset - size;
+        }
+        goto use_overflow_area;
+
+    case __va_float_reg:
+        if (ap->fp_offset < 128 + 48) {
+            ap->fp_offset += 16;
+            if (size == 8)
+                return ap->reg_save_area + ap->fp_offset - 16;
+            if (ap->fp_offset < 128 + 48) {
+                memcpy(ap->reg_save_area + ap->fp_offset - 8,
+                       ap->reg_save_area + ap->fp_offset, 8);
+                ap->fp_offset += 16;
+                return ap->reg_save_area + ap->fp_offset - 32;
+            }
+        }
+        goto use_overflow_area;
+
+    case __va_stack:
+    use_overflow_area:
+        ap->overflow_arg_area += size;
+        ap->overflow_arg_area = (char*)((long long)(ap->overflow_arg_area + align - 1) & -align);
+        return ap->overflow_arg_area - size;
+
+    default: /* should never happen */
+        abort();
+        return 0;
+    }
+}
+#endif