From e0560a2db9b7a1a29a47e7ebe4de668763e36b2d Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sb@m-labs.hk>
Date: Tue, 21 Jul 2020 13:50:33 +0800
Subject: [PATCH] expose libm functions to kernel

---
 default.nix                   |  2 +-
 src/Cargo.lock                |  7 +++++++
 src/runtime/Cargo.toml        |  1 +
 src/runtime/src/kernel/api.rs | 29 +++++++++++++++++++++++++++++
 4 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/default.nix b/default.nix
index 67ba91fe..52d46ce8 100644
--- a/default.nix
+++ b/default.nix
@@ -14,7 +14,7 @@ let
       version = "0.1.0";
 
       src = ./src;
-      cargoSha256 = "11kd1vmm4i4plqwxbsgrxia1ihs2szw1r7af8j645zib71f0qx87";
+      cargoSha256 = "04asmk07xc7asbpl15d9pgm31dd77lj9hkfgf76kcq6ds7l04k12";
 
       nativeBuildInputs = [
         pkgs.gnumake
diff --git a/src/Cargo.lock b/src/Cargo.lock
index bd5c453e..eb1b03a1 100644
--- a/src/Cargo.lock
+++ b/src/Cargo.lock
@@ -242,6 +242,12 @@ dependencies = [
  "libregister",
 ]
 
+[[package]]
+name = "libm"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c7d73b3f436185384286bd8098d17ec07c9a7d2388a6599f824d8502b529702a"
+
 [[package]]
 name = "libregister"
 version = "0.0.0"
@@ -412,6 +418,7 @@ dependencies = [
  "libboard_zynq",
  "libc",
  "libcortex_a9",
+ "libm",
  "libregister",
  "libsupport_zynq",
  "log",
diff --git a/src/runtime/Cargo.toml b/src/runtime/Cargo.toml
index 91173f01..e8dc899e 100644
--- a/src/runtime/Cargo.toml
+++ b/src/runtime/Cargo.toml
@@ -23,6 +23,7 @@ futures = { version = "0.3", default-features = false, features = ["async-await"
 async-recursion = "0.3"
 fatfs = { version = "0.3", features = ["core_io"], default-features = false }
 log_buffer = { version = "1.2" }
+libm = { version = "0.2", features = ["unstable"] }
 
 libboard_zynq = { git = "https://git.m-labs.hk/M-Labs/zc706.git" }
 libsupport_zynq = { default-features = false, git = "https://git.m-labs.hk/M-Labs/zc706.git" }
diff --git a/src/runtime/src/kernel/api.rs b/src/runtime/src/kernel/api.rs
index aba60193..1a63a608 100644
--- a/src/runtime/src/kernel/api.rs
+++ b/src/runtime/src/kernel/api.rs
@@ -1,3 +1,5 @@
+use libm;
+
 use crate::eh_artiq;
 use crate::rtio;
 use super::rpc::{rpc_send, rpc_send_async, rpc_recv};
@@ -16,6 +18,15 @@ macro_rules! api {
     }
 }
 
+macro_rules! api_libm_f64f64 {
+    ($i:ident) => ({
+        extern fn $i(x: f64) -> f64 {
+            libm::$i(x)
+        }
+        api!($i = $i)
+    })
+}
+
 pub fn resolve(required: &[u8]) -> Option<u32> {
     let api = &[
         // timing
@@ -117,14 +128,32 @@ pub fn resolve(required: &[u8]) -> Option<u32> {
         api!(__aeabi_memclr8),
         api!(__aeabi_memclr4),
         api!(__aeabi_memclr),
+
         // libc
         api!(memcmp, extern { fn memcmp(a: *const u8, b: *mut u8, size: usize); }),
+
         // exceptions
         api!(_Unwind_Resume = unwind::_Unwind_Resume),
         api!(__artiq_personality = eh_artiq::artiq_personality),
         api!(__artiq_raise = eh_artiq::raise),
         api!(__artiq_reraise = eh_artiq::reraise),
 
+        // libm
+        api_libm_f64f64!(log),
+        api_libm_f64f64!(log10),
+        api_libm_f64f64!(exp),
+        {
+            extern fn pow(x: f64, y: f64) -> f64 {
+                libm::pow(x, y)
+            }
+            api!(pow = pow)
+        },
+        api_libm_f64f64!(sin),
+        api_libm_f64f64!(cos),
+        api_libm_f64f64!(tan),
+        api_libm_f64f64!(asin),
+        api_libm_f64f64!(acos),
+        api_libm_f64f64!(atan),
     ];
     api.iter()
        .find(|&&(exported, _)| exported.as_bytes() == required)