1 files changed, 65 insertions, 0 deletions
diff --git a/tinyc/lib/va_list.c b/tinyc/lib/va_list.c
new file mode 100644
index 000000000..8749f46f8
--- /dev/null
+++ b/tinyc/lib/va_list.c
@@ -0,0 +1,65 @@
+/* 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 *memset(void *s, int c, __SIZE_TYPE__ n);
+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. */
+typedef struct {
+    unsigned int gp_offset;
+    unsigned int fp_offset;
+    union {
+        unsigned int overflow_offset;
+        char *overflow_arg_area;
+    };
+    char *reg_save_area;
+} __va_list_struct;
+
+void __va_start(__va_list_struct *ap, void *fp)
+{
+    memset(ap, 0, sizeof(__va_list_struct));
+    *ap = *(__va_list_struct *)((char *)fp - 16);
+    ap->overflow_arg_area = (char *)fp + ap->overflow_offset;
+    ap->reg_save_area = (char *)fp - 176 - 16;
+}
+
+void *__va_arg(__va_list_struct *ap,
+               enum __va_arg_type arg_type,
+               int size, int align)
+{
+    size = (size + 7) & ~7;
+    align = (align + 7) & ~7;
+    switch (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;
+            return ap->reg_save_area + ap->fp_offset - 16;
+        }
+        size = 8;
+        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();
+    }
+}
+#endif