shithub: mc

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Use correct shift in bigdiv.

    Test it.

--- a/libstd/bigint.myr

+++ b/libstd/bigint.myr

@@ -50,6 +50,8 @@

 	const bigshri	: (a : bigint#, b : uint64 -> bigint#)

 ;;

+const Base = 0x100000000ul

+

 const mkbigint = {v

 	var a

 	a = zalloc()

@@ -398,7 +400,7 @@

 	m = u.dig.len

 	n = v.dig.len

-	shift = nlz(v.dig[n - 1])

+	shift = 32-nlz(v.dig[n - 1])

 	bigshli(u, shift)

 	bigshli(v, shift)

 	for j = m - n; j >= 0; j--

@@ -412,10 +414,10 @@

 		qhat = (x + y)/z

 		rhat = (x + y) - (qhat * z)

 :divagain

-		if qhat > 0xfffffffful || qhat * w > ((rhat << 32) + w)

+		if qhat >= Base || (qhat * w) > ((rhat << 32) + w)

 			qhat--

 			rhat += z

-			if rhat <= 0xfffffffful

+			if rhat < Base

 				goto divagain

 			;;

 		;;

--- a/test/bigint.myr

+++ b/test/bigint.myr

@@ -23,4 +23,23 @@

 	n = std.bigfmt(buf[:], a)

 	std.put("%s\n", buf[:n])

+

+	match std.bigparse("1234_5678_1234_6789_6666_7777_8888")

+	| `std.Some val: a = val

+	| `std.None: std.die("Failed to parse a\n")

+	;;

+	match std.bigparse("1234_5678_1234_6789_6666_7777")

+	| `std.Some val: b = val

+	| `std.None: std.die("Failed to parse b\n")

+	;;

+

+	n = std.bigfmt(buf[:], a)

+	std.put("%s\n", buf[:n])

+	n = std.bigfmt(buf[:], b)

+	std.put("%s\n", buf[:n])

+

+	std.bigdiv(a, b)

+

+	n = std.bigfmt(buf[:], a)

+	std.put("%s\n", buf[:n])

 }