From f8d6d13a249d7a64cef40f428b5aa6359c5bda06 Mon Sep 17 00:00:00 2001
From: Nicolas Abril <nicolas.abril@protonmail.ch>
Date: Sat, 15 Jun 2024 19:32:21 +0200
Subject: [PATCH] Write log and atan2 as native hvm defs

---
 docs/builtins.md      | 16 ++++++++++++++++
 src/fun/builtins.bend | 17 +++++++++++++----
 2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/docs/builtins.md b/docs/builtins.md
index 109c164d..d1ffda39 100644
--- a/docs/builtins.md
+++ b/docs/builtins.md
@@ -226,3 +226,19 @@ A Natural Number can be written with literals with a `#` before the literal numb
 
 ## IO
 IO Functions are in the **next milestone**!
+
+## Numeric operations
+
+### log
+```py
+def log(x: f24, base: f24) -> f24
+```
+Computes the logarithm of `x` with the specified `base`.
+
+### atan2
+```py
+def atan2(x: f24, y: f24) -> f24
+```
+Computes the arctangent of `y / x`.
+
+Has the same behaviour as `atan2f` in the C math lib.
diff --git a/src/fun/builtins.bend b/src/fun/builtins.bend
index 822eef05..21d95372 100644
--- a/src/fun/builtins.bend
+++ b/src/fun/builtins.bend
@@ -95,7 +95,10 @@ print text = (IO/Call IO/MAGIC "PUT_TEXT" text @x (IO/Done IO/MAGIC x))
 #read_file path = (IO/Call IO/MAGIC "GET_FILE" path @x (IO/Done IO/MAGIC x))
 #write_file path text = (IO/Call IO/MAGIC "PUT_FILE" (path, text) @x (IO/Done IO/MAGIC x))
 
+# Returns a monotonically increasing nanosecond timestamp as an u48 encoded as a pair of u24s.
 get_time = (IO/Call IO/MAGIC "GET_TIME" * @x (IO/Done IO/MAGIC x))
+
+# Sleeps for the given number of nanoseconds, given by an u48 encoded as a pair of u24s.
 sleep hi_lo = (IO/Call IO/MAGIC "PUT_TIME" hi_lo @x (IO/Done IO/MAGIC x))
 
 
@@ -110,10 +113,16 @@ defer val = @x (x val)
 defer_arg defered arg = @x (defered x arg)
 undefer defered = (defered @x x)
 
-# log :: f24 -> f24 -> f24
+
+# Native numeric operations
+
+# log(x: f24, base: f24) -> f24
 # Computes the logarithm of `x` with the specified `base`.
-log x base = (| base x)
-# atan2 :: f24 -> f24 -> f24
+hvm log:
+  (x ($([|] $(x ret)) ret))
+
+# atan2(x: f24, y: f24) -> f24
 # Has the same behaviour as `atan2f` in the C math lib.
 # Computes the arctangent of the quotient of its two arguments.
-atan2 x y = (& x y)
+hvm atan2:
+  ($([&] $(y ret)) (y ret))