Scientific floats

benchmarks/float/exponentiation-by-squaring.out

@@ -1,2 +1,2 @@
-3.083945934529577e+53
-1.422023440989732e+137
+3.08394593452957709e+53
+1.42202344098973190e+137

bril-rs/bril2json/src/bril_grammar.lalrpop

@@ -160,6 +160,7 @@ Ident: String = {
     <s : IDENT_TOKEN> => s.to_string(),
     "true" => "true".to_owned(),
     "false" => "false".to_owned(),
+    "from" => "from".to_owned(),
 }
 
 Args: ParsingArgs = {

bril-rs/brillvm/Makefile

@@ -2,12 +2,12 @@ TESTS := ../../test/interp/core/*.bril \
          ../../test/interp/float/*.bril \
 		 ../../test/interp/ssa/*.bril \
 		 ../../test/interp/mem/*.bril \
-		 ../../test/interp/mixed/*[^r].bril # A hack to exclude store-char.bril by excluding any file ending in r.bril
+		 ../../test/interp/mixed/*[!r].bril # A hack to exclude store-char.bril by excluding any file ending in r.bril
 
 BENCHMARKS := ../../benchmarks/core/*.bril \
 			  ../../benchmarks/float/*.bril \
 			  ../../benchmarks/mem/*.bril \
-			  ../../benchmarks/mixed/*.bril
+			  ../../benchmarks/mixed/*[!k].bril # a hack to exclude random_walk.bril because it uses the char extension
 
 build:
 	cargo build

bril-rs/brillvm/runtime/Cargo.toml

@@ -6,7 +6,7 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-libc-print = "0.1"
+libc = { version = "0.2", default-features = false }
 
 # To properly set up the rt library for linking with LLVM
 [profile.dev]
@@ -15,4 +15,4 @@ lto = true
 
 [profile.release]
 panic = "abort"
-lto = true
+lto = true

bril-rs/brillvm/runtime/src/main.rs

@@ -7,45 +7,60 @@ use std::mem::size_of; */
 
 use core::ffi::{c_char, CStr};
 
-use libc_print::std_name::{print, println};
-
 #[no_mangle]
 pub extern "C" fn _bril_print_int(i: i64) {
-    print!("{}", i);
+    unsafe {
+        libc::printf(c"%lld".as_ptr().cast(), i);
+    }
 }
 
 #[no_mangle]
 pub extern "C" fn _bril_print_bool(b: bool) {
-    if b {
-        print!("true")
-    } else {
-        print!("false")
+    let c_str = if b { c"true" } else { c"false" };
+    unsafe {
+        libc::printf(c_str.as_ptr().cast());
     }
 }
 
 #[no_mangle]
 pub extern "C" fn _bril_print_float(f: f64) {
     if f.is_infinite() {
         if f.is_sign_negative() {
-            print!("-Infinity");
+            unsafe {
+                libc::printf(c"-Infinity".as_ptr().cast());
+            }
         } else {
-            print!("Infinity");
+            unsafe {
+                libc::printf(c"Infinity".as_ptr().cast());
+            }
         }
     } else if f.is_nan() {
-        print!("NaN");
+        unsafe {
+            libc::printf(c"NaN".as_ptr().cast());
+        }
+    } else if f != 0.0 && (f.abs() >= 1E10 || f.abs() <= 1E-10) {
+        unsafe {
+            libc::printf(c"%.17e".as_ptr().cast(), f);
+        }
     } else {
-        print!("{:.17}", f);
+        unsafe {
+            libc::printf(c"%.17lf".as_ptr().cast(), f);
+        }
     }
 }
 
 #[no_mangle]
 pub extern "C" fn _bril_print_sep() {
-    print!(" ");
+    unsafe {
+        libc::printf(c" ".as_ptr().cast());
+    }
 }
 
 #[no_mangle]
 pub extern "C" fn _bril_print_end() {
-    println!();
+    unsafe {
+        libc::printf(c"\n".as_ptr().cast());
+    }
 }
 
 #[no_mangle]

brili.ts

@@ -594,8 +594,12 @@ function evalInstr(instr: bril.Instruction, state: State): Action {
     let args = instr.args || [];
     let values = args.map(function (i) {
       let val = get(state.env, i);
-      if (Object.is(-0, val)) { return "-0.00000000000000000" };
-      if (typeof val == "number") { return val.toFixed(17) } else {return val.toString()}}
+      if (typeof val == "number") {
+        if ( Object.is(-0.0, val)) { return "-" + val.toFixed(17) }
+        else if (val != 0.0 && Math.abs(Math.log10(Math.abs(val))) >= 10) { return val.toExponential(17) }
+        else { return val.toFixed(17) }
+      }
+       else {return val.toString()}}
     );
     console.log(...values);
     return NEXT;

brilift/Makefile

@@ -1,7 +1,7 @@
 # Brilift only supports core Bril for now, so we select those tests &
 # benchmarks.
 TESTS := ../test/interp/core/*.bril ../test/interp/float/*.bril ../test/interp/mem/*.bril ../test/interp/mixed/*[!r].bril # A hack to exclude store-char.bril by excluding any file ending in r.bril
-BENCHMARKS := ../benchmarks/core/*.bril ../benchmarks/float/*.bril ../benchmarks/mem/*.bril ../benchmarks/mixed/*.bril
+BENCHMARKS := ../benchmarks/core/*.bril ../benchmarks/float/*.bril ../benchmarks/mem/*.bril ../benchmarks/mixed/*[!k].bril # A hack to exclude random_walk.bril because it uses the char extension
 
 CFLAGS := $(if $(TARGET),-target $(TARGET))
 BRILFLAGS := $(if $(TARGET),-t $(TARGET))
@@ -23,7 +23,7 @@ test: rt.o release
 
 .PHONY: benchmark
 benchmark: rt.o release
-	turnt -e brilift-aot -e brilift-jit $(TURNTARGS) $(BENCHMARKS)
+	turnt --diff -e brilift-aot -e brilift-jit $(TURNTARGS) $(BENCHMARKS)
 
 rt.o: rt.c
 	cc $(CFLAGS) -c -o $@ $^

brilift/rt.c

@@ -26,6 +26,8 @@ void _bril_print_float(double f) {
         } else {
             printf("Infinity");
         }
+    } else if ((f != 0.0) && ((fabs(f) >= 1E10) || (fabs(f) <= 1E-10))) {
+        printf("%.17e", f);
     } else {
         printf("%.17lf", f);
     }

brilift/src/rt.rs

@@ -19,6 +19,10 @@ pub extern "C" fn print_float(f: f64) {
         } else {
             print!("Infinity");
         }
+    } else if f != 0.0 && f.abs().log10() >= 10.0 {
+        print!("{}", format!("{f:.17e}").replace('e', "e+").as_str());
+    } else if f != 0.0 && f.abs().log10() <= -10.0 {
+        print!("{f:.17e}");
     } else {
         print!("{f:.17}");
     }

brilirs/src/interp.rs

@@ -198,6 +198,10 @@ impl fmt::Display for Value {
       Self::Bool(b) => write!(f, "{b}"),
       Self::Float(v) if v.is_infinite() && v.is_sign_positive() => write!(f, "Infinity"),
       Self::Float(v) if v.is_infinite() && v.is_sign_negative() => write!(f, "-Infinity"),
+      Self::Float(v) if v != &0.0 && v.abs().log10() >= 10.0 => {
+        f.write_str(format!("{v:.17e}").replace('e', "e+").as_str())
+      }
+      Self::Float(v) if v != &0.0 && v.abs().log10() <= -10.0 => write!(f, "{v:.17e}"),
       Self::Float(v) => write!(f, "{v:.17}"),
       Self::Char(c) => write!(f, "{c}"),
       Self::Pointer(p) => write!(f, "{p:?}"),
@@ -213,6 +217,12 @@ fn optimized_val_output<T: std::io::Write>(out: &mut T, val: &Value) -> Result<(
     Value::Float(f) if f.is_infinite() && f.is_sign_positive() => out.write_all(b"Infinity"),
     Value::Float(f) if f.is_infinite() && f.is_sign_negative() => out.write_all(b"-Infinity"),
     Value::Float(f) if f.is_nan() => out.write_all(b"NaN"),
+    Value::Float(f) if f != &0.0 && f.abs().log10() >= 10.0 => {
+      out.write_all(format!("{f:.17e}").replace('e', "e+").as_bytes())
+    }
+    Value::Float(f) if f != &0.0 && f.abs().log10() <= -10.0 => {
+      out.write_all(format!("{f:.17e}").as_bytes())
+    }
     Value::Float(f) => out.write_all(format!("{f:.17}").as_bytes()),
     Value::Char(c) => {
       let buf = &mut [0_u8; 2];

docs/lang/float.md

@@ -44,6 +44,8 @@ Printing
 --------
 
 The [core `print` operation](./core.md#miscellaneous) prints `float` values with 17 decimal digits of precision, including trailing zeros.
-(This is like using the `%.17lf` format specifier in C's `printf`.)
+For values with magnitude 10¹⁰, it uses exponential notation with suffixes like `e+12`.
+(In terms of C's `printf`, this is like using the `%.17lf` format specifier for small values and `%.17e` for large values, i.e., when `f.abs().log10().abs >= 10`.)
+
 Positive and negative zero, while they are equal according to `feq`, look different when printed.
 Not-a-number values are printed as `NaN`; infinite values are printed as the strings `Infinity` or `-Infinity`.

test/interp/float/float_special.bril

@@ -5,12 +5,18 @@
   print v0;
   print v1;
   print res;
-  # v2: float = const 1e6;
-  # v3: float = const 1E-6;
-  # v4: float = const -1E+6;
-  # v5: float = const +.11e12;
-  # print v2;
-  # print v3;
-  # print v4;
-  # print v5;
+  v2: float = const 1e6;
+  v3: float = const 1E-6;
+  v4: float = const -1E+6;
+  v5: float = const +.11e12;
+  print v2;
+  print v3;
+  print v4;
+  print v5;
+  v6: float = const 1e21;
+  v7: float = const 1e-21;
+  print v6;
+  print v7;
+  v8: float = const 1e5;
+  print v8;
 }

test/interp/float/float_special.out

@@ -1,3 +1,10 @@
 0.00000000000000000
 -0.00000000000000000
 true
+1000000.00000000000000000
+0.00000100000000000
+-1000000.00000000000000000
+1.10000000000000000e+11
+1.00000000000000000e+21
+9.99999999999999908e-22
+100000.00000000000000000