diff --git a/console.asm b/console.asm
index cb03e84..b1ef2f3 100644
--- a/console.asm
+++ b/console.asm
@@ -77,6 +77,11 @@ printf:
 			je	.rep_c
 			cmp	byte [rdi+1], 's'
 			je	.rep_s
+			
+			;--- invalid specifier ---;
+			mov	byte [r11], '%'
+			inc	r10 ;assuming args were passed for invalid specifiers !
+			jmp	.continue
 
 			;--- %d ---;
 			.rep_d:
diff --git a/tests.asm b/tests.asm
index 09d2e61..1d9b357 100644
--- a/tests.asm
+++ b/tests.asm
@@ -70,7 +70,7 @@ section	.rodata
 	msgPuts		db	NL,NL,"# puts()",NL,EOS
 	msgPuts1	db	"puts() test",EOS
 	; printf()
-	testStr		db	"Testing: %s, %%, %s, %s, %s, %s, %s, %s, %s, %d, %s",NL,EOS
+	testStr		db	"Testing: %s, %%, %s, %s, %f, %s, %d, %s, %s, %x, %s, %s, %d, %s",NL,EOS
 	tS1		db	"one",EOS
 	tS2		db	"two",EOS
 	tS3		db	"three",EOS
@@ -82,7 +82,7 @@ section	.rodata
 	tS9		db	"noin",EOS
 	msgPrintf	db	NL,"# printf()",EOS
 	msgPrintf1	db	"TEST printf()",NL,EOS
-	msgPrintf2	db	"TEST printf(testStr, tS1, tS2, tS3, tS4, tS5, tS6, tS7, tS8, num1, tS9)",NL,EOS
+	msgPrintf2	db	"TEST printf(testStr, tS1, tS2, tS3, invalid1, tS4, num4, tS5, tS6, invalid2, tS7, tS8, num1, tS9)",NL,EOS
 	msgPrintf2b	db	"Return value: %d",NL,EOS
 	; min() / minu()
 	msgMin		db	NL,"# min() / minu()",EOS
@@ -223,7 +223,7 @@ main:
 	lea	rdi, [rel msgPrintf1]
 	call	printf
 
-	; TEST: printf(testStr, tS1, tS2, tS3, tS4, tS5, tS6, tS7, tS8, num1, tS9)
+	; TEST printf(testStr, tS1, tS2, tS3, invalid1, tS4, num4, tS5, tS6, invalid2, tS7, tS8, num1, tS9)
 	lea	rdi, [rel msgPrintf2]
 	call	printf
 
@@ -231,15 +231,18 @@ main:
 	lea	rsi, [rel tS1]
 	lea	rdx, [rel tS2]
 	lea	rcx, [rel tS3]
-	lea	r8, [rel tS4]
-	lea	r9, [rel tS5]
+	mov	r8, 0
+	lea	r9, [rel tS4]
 	push	tS9
 	push	qword [rel num1]
 	push	tS8
 	push	tS7
+	push	0
 	push	tS6
+	push	tS5
+	push	qword [num4]
 	call	printf
-	add	rsp, 40 ;cleanup stack, 8*5
+	add	rsp, 8*8
 	mov	rsi, rax
 	lea	rdi, [msgPrintf2b]
 	call	printf