From 479f3b934304a1e0b18fc288efafda3a680fe159 Mon Sep 17 00:00:00 2001
From: Dale Weiler <killfieldengine@gmail.com>
Date: Fri, 8 Mar 2013 03:46:25 +0000
Subject: [PATCH] Implemented __builtin_exp

---
 parser.c                  | 49 ++++++++++++++++++++++++++++++++++++---
 tests/exponentiation.qc   |  3 +++
 tests/exponentiation.tmpl |  1 +
 3 files changed, 50 insertions(+), 3 deletions(-)

diff --git a/parser.c b/parser.c
index 6ab55e3..98c0c9f 100644
--- a/parser.c
+++ b/parser.c
@@ -121,6 +121,7 @@ static ast_value* parser_create_array_setter_proto(parser_t *parser, ast_value *
 static ast_value* parser_create_array_getter_proto(parser_t *parser, ast_value *array, const ast_expression *elemtype, const char *funcname);
 static ast_value *parse_typename(parser_t *parser, ast_value **storebase, ast_value *cached_typedef);
 static ast_expression *parser_builtin_pow(parser_t *);
+static ast_expression *parser_builtin_exp(parser_t *);
 
 static void parseerror(parser_t *parser, const char *fmt, ...)
 {
@@ -1855,6 +1856,8 @@ static bool parse_sya_operand(parser_t *parser, shunt *sy, bool with_labels)
             }
             if (!strcmp(parser_tokval(parser), "__builtin_pow"))
                 var = parser_builtin_pow(parser);
+            if (!strcmp(parser_tokval(parser), "__builtin_exp"))
+                var = parser_builtin_exp(parser);
                 
             if (!var) {
                 char *correct = NULL;
@@ -3325,11 +3328,11 @@ ast_expression *parser_builtin_pow(parser_t *parser) {
      *   float value = 1.0f;
      *   while (y > 0) {
      *     while (!(y&1)) {
-     *       y *= 2;
+     *       y *= 0.25f;
      *       x *= x;
      *     }
-     *     y = y - 1;
-     *     value = x * value;
+     *     y--;
+     *     value *= x;
      *   }
      *   return value;
      * }      
@@ -3458,6 +3461,46 @@ ast_expression *parser_builtin_pow(parser_t *parser) {
     return (ast_expression*)pow_func_val;
 }
 
+#ifndef M_E
+#define M_E 2.71828182845905
+#endif
+static ast_expression *parser_builtin_exp(parser_t *parser) {
+    /*
+     * float __builtin_exp(float x) {
+     *     return __builtin_exp(E, x);
+     * }
+     */ 
+    static ast_value *exp_func_val = NULL;
+
+    if (!exp_func_val) {
+        ast_function *exp_func         = NULL;
+        ast_value    *arg              = ast_value_new   (parser_ctx(parser), "x", TYPE_FLOAT);
+        ast_block    *exp_body         = ast_block_new   (parser_ctx(parser));
+        ast_call     *exp_call         = ast_call_new    (parser_ctx(parser), parser_builtin_pow(parser));
+        exp_func_val                   = ast_value_new   (parser_ctx(parser), "__builtin_exp", TYPE_FUNCTION);
+        exp_func_val->expression.next  = (ast_expression*)ast_value_new(parser_ctx(parser), "<float>", TYPE_FLOAT);
+        exp_func                       = ast_function_new(parser_ctx(parser), "__builtin_exp", exp_func_val);
+
+        vec_push(exp_call->params, (ast_expression*)parser_const_float(parser, M_E));
+        vec_push(exp_call->params, (ast_expression*)arg);
+
+        vec_push(exp_body->exprs,
+            (ast_expression*)ast_return_new(
+                parser_ctx(parser),
+                (ast_expression*)exp_call
+            )
+        );
+
+        vec_push(exp_func_val->expression.params, arg);
+        vec_push(exp_func->blocks, exp_body);
+
+        vec_push(parser->functions, exp_func);
+        vec_push(parser->globals, (ast_expression*)exp_func_val);
+    }
+
+    return (ast_expression*)exp_func_val;
+}
+
 /* parse computed goto sides */
 static ast_expression *parse_goto_computed(parser_t *parser, ast_expression **side) {
     ast_expression *on_true;
diff --git a/tests/exponentiation.qc b/tests/exponentiation.qc
index f3ab7d3..5b8f24e 100644
--- a/tests/exponentiation.qc
+++ b/tests/exponentiation.qc
@@ -8,4 +8,7 @@ void main() {
 
     hundy -= 90; // 100-90 = 10
     print(ftos(hundy ** 2), "\n"); // prints: 100
+
+    hundy = 10.0f;
+    print(ftos(__builtin_exp(hundy)), "\n"); // prints: 22026.5
 }
diff --git a/tests/exponentiation.tmpl b/tests/exponentiation.tmpl
index 47741ea..0aa7f85 100644
--- a/tests/exponentiation.tmpl
+++ b/tests/exponentiation.tmpl
@@ -6,3 +6,4 @@ C: -std=gmqcc
 E: $null
 M: 100
 M: 100
+M: 22026.5
-- 
2.39.2