diff --git a/tester-psw.mac b/tester-psw.mac
index e6db5f3..91538a9 100644
--- a/tester-psw.mac
+++ b/tester-psw.mac
@@ -24,7 +24,7 @@ psw_store_retrieve_fail:
 	MOV	R2,R0
 	CALL	print_binary
 
-	MOV	#psw_fail_text, R0
+	MOV	#psw_store_retrieve_fail_text, R0
 	CALL	print_start
 	RET
 
@@ -34,8 +34,86 @@ psw_flags_trigger:
 	CLZ
 	CLN
 
-; TODO
+; test zero bit
+	MOV	#0,R1
+	TST	R1
+	BEQ	psw_trigger_1_next
+; store test number
+	MOV	#1.,R2
+	JMP	psw_trigger_fail
 
+psw_trigger_1_next:
+	MOV	#128.,R1
+	TST	R1
+	BNE	psw_trigger_2_next
+	MOV	#2.,R2
+	JMP	psw_trigger_fail
+
+psw_trigger_2_next:
+
+; test overflow bit (overflow)
+	MOV	#127.,R1
+	INCB	R1
+	BVS	psw_trigger_3_next
+	MOV	#3.,R2
+	JMP	psw_trigger_fail
+
+; test overflow bit (underflow)
+psw_trigger_3_next:
+	MOV	#-128.,R1
+	DECB	R1
+	BVS	psw_trigger_4_next
+	MOV	#4.,R2
+	JMP	psw_trigger_fail
+
+psw_trigger_4_next:
+; test minus bit
+	MOV	#127.,R1
+	INCB	R1
+	BMI	psw_trigger_5_next
+	MOV	#5.,R2
+	JMP	psw_trigger_fail
+
+psw_trigger_5_next:
+	MOV	#128.,R1
+	DECB	R1
+	BPL	psw_trigger_6_next
+	MOV	#6.,R2
+	JMP	psw_trigger_fail
+
+psw_trigger_6_next:
+; carry flag test
+	MOV	#128.,R1
+	ASLB	R1
+	BCS	psw_trigger_7_next
+	MOV	#7.,R2
+	JMP	psw_trigger_fail
+
+psw_trigger_7_next:
+	MOV	#64.,R1
+	ASLB	R1
+	BCC	psw_trigger_8_next
+	MOV	#8.,R2
+	JMP	psw_trigger_fail
+
+psw_trigger_8_next:
 	RET
 
-psw_fail_text:	.ASCII	"MFPS / MTPS handling FAIL\r\n\x00"
+psw_trigger_fail:
+; emit test number
+	MOV	R2,R0
+	CALL	print_binary
+; emit flags
+	MFPS	R0
+	CALL	print_binary
+; emit text
+	MOV	#psw_trigger_fail_text,R0
+	CALL	print_start
+	RET
+	
+psw_store_retrieve_fail_text:
+	.ASCII	"MFPS / MTPS handling FAIL\r\n\x00"
+
+psw_trigger_fail_text:
+	.ASCII	"PSW trigger fail\r\n\x00"
+.EVEN
diff --git a/tester.mac b/tester.mac
index d5b3de9..f2ee34a 100644
--- a/tester.mac
+++ b/tester.mac
@@ -96,6 +96,7 @@ bit_seperator2:
 
 textstart:	.ASCII	"tester running...\r\n\x00"
 textfin:	.ASCII	"tester finished\r\n\x00"
+.EVEN
 
 textbuffer:	.BLKB	256.