X-Git-Url: https://pd.if.org/git/?p=zos;a=blobdiff_plain;f=klib%2Fbitops.s;fp=klib%2Fbitops.s;h=2771bcb60c99f5732f06912c86b433604e58bfa5;hp=0000000000000000000000000000000000000000;hb=5c0e560e481e2e97b793f7574e849a5882781df9;hpb=e57b692bd3a86ee40fd89416a06fd696f1ff3bf9

diff --git a/klib/bitops.s b/klib/bitops.s
new file mode 100644
index 0000000..2771bcb
--- /dev/null
+++ b/klib/bitops.s
@@ -0,0 +1,10 @@
+; round up to a power of two
+logtwoup:
+	xor eax, eax
+	bsr rsi, rdi ; rsi has the log 2 rounded down
+	bts rax, rsi
+	cmp rax, rdi
+	jz .done
+	shr rax, 1
+.done:
+	ret