corrected function signatures, optimized signbit

Author: ZERICO2005

src/libc/isinfl.src

@@ -4,7 +4,7 @@
 
 	public	__isinfl
 
-; int _isinfl(long double)
+; bool _isinfl(long double)
 __isinfl:
 	pop	bc, hl, de
 	xor	a, a

src/libc/isnanl.src

@@ -4,7 +4,7 @@
 
 	public	__isnanl
 
-; int _isnanl(long double)
+; bool _isnanl(long double)
 __isnanl:
 	pop	bc, hl, de
 	or	a, a

src/libc/issubnormall.src

@@ -4,7 +4,7 @@
 
 	public	__issubnormall
 
-; int _issubnormall(long double)
+; bool _issubnormall(long double)
 __issubnormall:
 	pop	bc, hl, de
 	or	a, a

src/libc/iszerol.src

@@ -4,7 +4,7 @@
 
 	public	__iszerol
 
-; int iszerol(long double)
+; bool iszerol(long double)
 __iszerol:
 	pop	bc, hl, de
 	xor	a, a

src/libc/signbitf.src

@@ -9,6 +9,5 @@ __signbitf:
 	ld	hl, 6
 	add	hl, sp
 	ld	a, (hl)
-	rla
-	sbc	a, a
+	rlca	; faster than rla \ sbc a, a
 	ret

src/libc/signbitl.src

@@ -9,6 +9,5 @@ __signbitl:
 	ld	hl, 10
 	add	hl, sp
 	ld	a, (hl)
-	rla
-	sbc	a, a
+	rlca	; faster than rla \ sbc a, a
 	ret