tests/misc: Add a test for correct CTR and LR updating by branches

This adds a test with a bdnzl followed immediately by a bdnz, to check
that CTR and LR both get evaluated and written back correctly in this
situation.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

tests/misc/head.S

@@ -137,3 +137,28 @@ test_mtpvr:
     mtlr %r0
 
     blr
+
+/* Test that bdnz and bdnzl update CTR and LR correctly */
+	.global	test_bdnzl
+test_bdnzl:
+	mflr	%r10
+	mfcr	%r11
+	li	%r0,0xf8
+	mtctr	%r0
+	lis	%r0,0x2000
+	mtcr	%r0
+	addpcis	%r9,0
+1:	bdnztl	27,3f
+2:	bdnzt	14,4f
+3:	nop
+4:	li	%r3,1
+	addi	%r9,%r9,2b-1b
+	mflr	%r8
+	cmpd	%r8,%r9
+	bne	9f
+	mfctr	%r7
+	cmpdi	%r7,0xf6
+	bne	9f
+	li	%r3,0
+9:	mtlr	%r10
+	blr

tests/misc/misc.c

@@ -14,6 +14,7 @@ extern long test_addpcis_1(void);
 extern long test_addpcis_2(void);
 extern long test_mfpvr(void);
 extern long test_mtpvr(void);
+extern long test_bdnzl(void);
 
 // i < 100
 void print_test_number(int i)
@@ -58,5 +59,12 @@ int main(void)
 	} else
 		puts(PASS);
 
+	print_test_number(5);
+	if (test_bdnzl() != 0) {
+		fail = 1;
+		puts(FAIL);
+	} else
+		puts(PASS);
+
 	return fail;
 }

tests/test_misc.console_out

@@ -2,3 +2,4 @@ Test 01:PASS
 Test 02:PASS
 Test 03:PASS
 Test 04:PASS
+Test 05:PASS