1 files changed, 82 insertions, 0 deletions
diff --git a/third_party/rust/ryu/src/pretty/mantissa.rs b/third_party/rust/ryu/src/pretty/mantissa.rs
new file mode 100644
index 0000000000..0149f5cffe
--- /dev/null
+++ b/third_party/rust/ryu/src/pretty/mantissa.rs
@@ -0,0 +1,82 @@
+use crate::digit_table::*;
+use core::ptr;
+
+#[cfg_attr(feature = "no-panic", inline)]
+pub unsafe fn write_mantissa_long(mut output: u64, mut result: *mut u8) {
+    if (output >> 32) != 0 {
+        // One expensive 64-bit division.
+        let mut output2 = (output - 100_000_000 * (output / 100_000_000)) as u32;
+        output /= 100_000_000;
+
+        let c = output2 % 10_000;
+        output2 /= 10_000;
+        let d = output2 % 10_000;
+        let c0 = (c % 100) << 1;
+        let c1 = (c / 100) << 1;
+        let d0 = (d % 100) << 1;
+        let d1 = (d / 100) << 1;
+        ptr::copy_nonoverlapping(
+            DIGIT_TABLE.as_ptr().offset(c0 as isize),
+            result.offset(-2),
+            2,
+        );
+        ptr::copy_nonoverlapping(
+            DIGIT_TABLE.as_ptr().offset(c1 as isize),
+            result.offset(-4),
+            2,
+        );
+        ptr::copy_nonoverlapping(
+            DIGIT_TABLE.as_ptr().offset(d0 as isize),
+            result.offset(-6),
+            2,
+        );
+        ptr::copy_nonoverlapping(
+            DIGIT_TABLE.as_ptr().offset(d1 as isize),
+            result.offset(-8),
+            2,
+        );
+        result = result.offset(-8);
+    }
+    write_mantissa(output as u32, result);
+}
+
+#[cfg_attr(feature = "no-panic", inline)]
+pub unsafe fn write_mantissa(mut output: u32, mut result: *mut u8) {
+    while output >= 10_000 {
+        let c = output - 10_000 * (output / 10_000);
+        output /= 10_000;
+        let c0 = (c % 100) << 1;
+        let c1 = (c / 100) << 1;
+        ptr::copy_nonoverlapping(
+            DIGIT_TABLE.as_ptr().offset(c0 as isize),
+            result.offset(-2),
+            2,
+        );
+        ptr::copy_nonoverlapping(
+            DIGIT_TABLE.as_ptr().offset(c1 as isize),
+            result.offset(-4),
+            2,
+        );
+        result = result.offset(-4);
+    }
+    if output >= 100 {
+        let c = (output % 100) << 1;
+        output /= 100;
+        ptr::copy_nonoverlapping(
+            DIGIT_TABLE.as_ptr().offset(c as isize),
+            result.offset(-2),
+            2,
+        );
+        result = result.offset(-2);
+    }
+    if output >= 10 {
+        let c = output << 1;
+        ptr::copy_nonoverlapping(
+            DIGIT_TABLE.as_ptr().offset(c as isize),
+            result.offset(-2),
+            2,
+        );
+    } else {
+        *result.offset(-1) = b'0' + output as u8;
+    }
+}