1 files changed, 57 insertions, 0 deletions
diff --git a/src/Runtime/__va_arg.c b/src/Runtime/__va_arg.c
new file mode 100644
index 0000000..fd0e182
--- /dev/null
+++ b/src/Runtime/__va_arg.c
@@ -0,0 +1,57 @@
+typedef struct {
+  char gpr;
+  char fpr;
+  char reserved[2];
+  char* input_arg_area;
+  char* reg_save_area;
+} va_list[1];
+
+typedef enum {
+  ARGPOINTER,
+  WORD,
+  DOUBLEWORD,
+  REAL,
+} _va_arg_type;
+
+#define ALIGN(addr, amount) (((unsigned int)(addr) + ((amount)-1)) & ~((amount)-1))
+
+void* __va_arg(va_list ap, _va_arg_type type) {
+  char* addr;
+  char* curGprPtr = &(ap->gpr);
+  int curGpr = ap->gpr;
+  int max = 8;
+  int size = 4;
+  int inc = 1;
+  int even = 0;
+  int fprOffset = 0;
+  int regSize = 4;
+
+  if (type == 3) {
+    curGprPtr = &(ap->fpr);
+    curGpr = ap->fpr;
+    size = 8;
+    fprOffset = 8 * 4;
+    regSize = 8;
+  }
+  if (type == 2) {
+    size = 8;
+    max = max - 1;
+    if (curGpr & 1)
+      even = 1;
+    inc = 2;
+  }
+  if (curGpr < max) {
+    curGpr += even;
+    addr = ap->reg_save_area + fprOffset + (curGpr * regSize);
+    *curGprPtr = curGpr + inc;
+  } else {
+    *curGprPtr = 8;
+    addr = ap->input_arg_area;
+    addr = (char*)ALIGN(addr, size);
+    ap->input_arg_area = addr + size;
+  }
+  if (type == ARGPOINTER)
+    addr = *((char**)addr);
+
+  return addr;
+}