Flesh out algorithms for addition, subtraction, multiplication, divis…

…ion, and remainder (#143)

* Add `toFixed`, `toPrecision`, and `toExponential`

* Define AO to massage a potential Decimal128 value to an actual one

* Say that Decimal128 values aren't ECMAScript language values

* Inline AO used only in the constructor

* Fix references to undefined variables and mark an in-progres spot

* Flesh out `round` method

* Fix specification for exponent in `divide`

* Add checks for rounding mode

* Flesh out constructor

* Add brand checks

* Add links

* Add reference for rounding

* Add more IEEE 754 references

* Use "Otherwise"

* Add note about how we convert from Number

relates to #122

.github/workflows/lint.yaml

@@ -16,7 +16,7 @@ jobs:
       - name: ensure no line starts with tabs
       - run: |
           for f in *emu; do
-            if ! [ grep '^\t' "$f"]; then
+            if ! [ grep '^\t' "$f" ]; then
               echo "$f has lines that begin with a tab";
               exit 1;
             fi

Makefile

@@ -2,8 +2,8 @@
 
 all: index.html
 
-index.html:
-	npx ecmarkup --lint-spec --strict --load-biblio @tc39/ecma262-biblio --load-biblio @tc39/ecma402-biblio spec.emu $<
+index.html: spec.emu intl.emu
+	npx ecmarkup --lint-spec --strict --load-biblio @tc39/ecma262-biblio --load-biblio @tc39/ecma402-biblio spec.emu $@
 
 clean:
 	rm -f index.html