From 36ec4e7d9be760da2943ed854629390b325cb6ba Mon Sep 17 00:00:00 2001
From: Matthew Waltz <matthewwaltzis@gmail.com>
Date: Thu, 24 Oct 2024 20:37:30 -0600
Subject: [PATCH] [libc] add _isblank

---
 src/libc/include/ctype.h |  2 ++
 src/libc/isblank.src     | 16 ++++++++++++++++
 2 files changed, 18 insertions(+)
 create mode 100644 src/libc/isblank.src

diff --git a/src/libc/include/ctype.h b/src/libc/include/ctype.h
index 1543446fb..60c3d639e 100644
--- a/src/libc/include/ctype.h
+++ b/src/libc/include/ctype.h
@@ -9,6 +9,8 @@ int isalnum(int c);
 
 int isalpha(int c);
 
+int isblank(int c);
+
 int iscntrl(int c);
 
 int isdigit(int c);
diff --git a/src/libc/isblank.src b/src/libc/isblank.src
new file mode 100644
index 000000000..a6a780d57
--- /dev/null
+++ b/src/libc/isblank.src
@@ -0,0 +1,16 @@
+	assume	adl=1
+
+	section	.text
+	public	_isblank
+_isblank:
+	pop	de
+	ex	(sp),hl
+	push	de
+	ld	a,l
+	cp	a,32
+	ret	z
+	cp	a,9
+	ret	z
+	or	a,a
+	sbc	hl,hl
+	ret