Another attempt at making MIPS happy

(I really don't understand how arithmetic makes it segfault...)

Author: scottmcm

build.rs

@@ -129,11 +129,15 @@ mod tests {
             Divsf3,
             Divdf3,
 
-            // int/add.rs
+            // int/addsub.rs
             AddU128,
             AddI128,
             AddoU128,
             AddoI128,
+            SubU128,
+            SubI128,
+            SuboU128,
+            SuboI128,
 
             // int/mul.rs
             Muldi3,
@@ -160,12 +164,6 @@ mod tests {
             Lshrdi3,
             Lshrti3,
 
-            // int/sub.rs
-            SubU128,
-            SubI128,
-            SuboU128,
-            SuboI128,
-
             // int/udiv.rs
             Udivdi3,
             Udivmoddi4,
@@ -390,7 +388,7 @@ fn addsf3() {
 
         fn prologue() -> &'static str {
             "
-use compiler_builtins::int::add::rust_u128_add;
+use compiler_builtins::int::addsub::rust_u128_add;
 
 static TEST_CASES: &[((u128, u128), u128)] = &[
 "
@@ -448,7 +446,7 @@ fn u128_add() {
 
         fn prologue() -> &'static str {
             "
-use compiler_builtins::int::add::rust_i128_add;
+use compiler_builtins::int::addsub::rust_i128_add;
 
 static TEST_CASES: &[((i128, i128), i128)] = &[
 "
@@ -508,7 +506,7 @@ fn i128_add() {
 
         fn prologue() -> &'static str {
             "
-use compiler_builtins::int::add::rust_u128_addo;
+use compiler_builtins::int::addsub::rust_u128_addo;
 
 static TEST_CASES: &[((u128, u128), (u128, bool))] = &[
 "
@@ -568,7 +566,7 @@ fn u128_addo() {
 
         fn prologue() -> &'static str {
             "
-use compiler_builtins::int::add::rust_i128_addo;
+use compiler_builtins::int::addsub::rust_i128_addo;
 
 static TEST_CASES: &[((i128, i128), (i128, bool))] = &[
 "
@@ -3514,7 +3512,7 @@ fn subsf3() {
 
         fn prologue() -> &'static str {
             "
-use compiler_builtins::int::sub::rust_u128_sub;
+use compiler_builtins::int::addsub::rust_u128_sub;
 
 static TEST_CASES: &[((u128, u128), u128)] = &[
 "
@@ -3572,7 +3570,7 @@ fn u128_sub() {
 
         fn prologue() -> &'static str {
             "
-use compiler_builtins::int::sub::rust_i128_sub;
+use compiler_builtins::int::addsub::rust_i128_sub;
 
 static TEST_CASES: &[((i128, i128), i128)] = &[
 "
@@ -3632,7 +3630,7 @@ fn i128_sub() {
 
         fn prologue() -> &'static str {
             "
-use compiler_builtins::int::sub::rust_u128_subo;
+use compiler_builtins::int::addsub::rust_u128_subo;
 
 static TEST_CASES: &[((u128, u128), (u128, bool))] = &[
 "
@@ -3692,7 +3690,7 @@ fn u128_subo() {
 
         fn prologue() -> &'static str {
             "
-use compiler_builtins::int::sub::rust_i128_subo;
+use compiler_builtins::int::addsub::rust_i128_subo;
 
 static TEST_CASES: &[((i128, i128), (i128, bool))] = &[
 "

src/int/add.rs

@@ -0,0 +1,122 @@
+use int::LargeInt;
+use int::Int;
+
+trait UAddSub: LargeInt {
+    fn uadd(self, other: Self) -> Self {
+        let (low, carry) = self.low().overflowing_add(other.low());
+        let high = self.high().wrapping_add(other.high());
+        let carry = if carry { Self::HighHalf::ONE } else { Self::HighHalf::ZERO };
+        Self::from_parts(low, high.wrapping_add(carry))
+    }
+    fn uadd_one(self) -> Self {
+        let (low, carry) = self.low().overflowing_add(Self::LowHalf::ONE);
+        let carry = if carry { Self::HighHalf::ONE } else { Self::HighHalf::ZERO };
+        Self::from_parts(low, self.high().wrapping_add(carry))
+    }
+    fn usub(self, other: Self) -> Self {
+        let uneg = (!other).uadd_one();
+        self.uadd(uneg)
+    }
+}
+
+impl UAddSub for u128 {}
+
+trait AddSub: Int
+    where <Self as Int>::UnsignedInt: UAddSub
+{
+    fn add(self, other: Self) -> Self {
+        Self::from_unsigned(self.unsigned().uadd(other.unsigned()))
+    }
+    fn sub(self, other: Self) -> Self {
+        Self::from_unsigned(self.unsigned().usub(other.unsigned()))
+    }
+}
+
+impl AddSub for u128 {}
+impl AddSub for i128 {}
+
+trait Addo: AddSub
+    where <Self as Int>::UnsignedInt: UAddSub
+{
+    fn addo(self, other: Self, overflow: &mut i32) -> Self {
+        *overflow = 0;
+        let result = AddSub::add(self, other);
+        if other >= Self::ZERO {
+            if result < self {
+                *overflow = 1;
+            }
+        } else {
+            if result >= self {
+                *overflow = 1;
+            }
+        }
+        result
+    }
+}
+
+impl Addo for i128 {}
+impl Addo for u128 {}
+
+trait Subo: AddSub
+    where <Self as Int>::UnsignedInt: UAddSub
+{
+    fn subo(self, other: Self, overflow: &mut i32) -> Self {
+        *overflow = 0;
+        let result = AddSub::sub(self, other);
+        if other >= Self::ZERO {
+            if result > self {
+                *overflow = 1;
+            }
+        } else {
+            if result <= self {
+                *overflow = 1;
+            }
+        }
+        result
+    }
+}
+
+impl Subo for i128 {}
+impl Subo for u128 {}
+
+#[cfg_attr(not(stage0), lang = "i128_add")]
+pub fn rust_i128_add(a: i128, b: i128) -> i128 {
+    rust_u128_add(a as _, b as _) as _
+}
+#[cfg_attr(not(stage0), lang = "i128_addo")]
+pub fn rust_i128_addo(a: i128, b: i128) -> (i128, bool) {
+    let mut oflow = 0;
+    let r = a.addo(b, &mut oflow);
+    (r, oflow != 0)
+}
+#[cfg_attr(not(stage0), lang = "u128_add")]
+pub fn rust_u128_add(a: u128, b: u128) -> u128 {
+    a.add(b)
+}
+#[cfg_attr(not(stage0), lang = "u128_addo")]
+pub fn rust_u128_addo(a: u128, b: u128) -> (u128, bool) {
+    let mut oflow = 0;
+    let r = a.addo(b, &mut oflow);
+    (r, oflow != 0)
+}
+
+#[cfg_attr(not(stage0), lang = "i128_sub")]
+pub fn rust_i128_sub(a: i128, b: i128) -> i128 {
+    rust_u128_sub(a as _, b as _) as _
+}
+#[cfg_attr(not(stage0), lang = "i128_subo")]
+pub fn rust_i128_subo(a: i128, b: i128) -> (i128, bool) {
+    let mut oflow = 0;
+    let r = a.subo(b, &mut oflow);
+    (r, oflow != 0)
+}
+#[cfg_attr(not(stage0), lang = "u128_sub")]
+pub fn rust_u128_sub(a: u128, b: u128) -> u128 {
+    a.sub(b)
+}
+#[cfg_attr(not(stage0), lang = "u128_subo")]
+pub fn rust_u128_subo(a: u128, b: u128) -> (u128, bool) {
+    let mut oflow = 0;
+    let r = a.subo(b, &mut oflow);
+    (r, oflow != 0)
+}

src/int/addsub.rs

@@ -12,11 +12,10 @@ macro_rules! os_ty {
     }
 }
 
-pub mod add;
+pub mod addsub;
 pub mod mul;
 pub mod sdiv;
 pub mod shift;
-pub mod sub;
 pub mod udiv;
 
 /// Trait for some basic operations on integers