[Patch, AArch64] Extend the range of system registers that can be specified using the S3_<op1>_<Cn>_<Cm>_<op2> form

[Yufeng Zhang <Yufeng dot Zhang at arm dot com>]

Hi,

This patch changes GAS to allow more system registers to be specified 
using S3_<op1>_<Cn>_<Cm>_<op2>.  This relaxation enables the assembler 
to accept more system registers without the need to add/maintain more 
tables of system registers with specific names.

The disassembler has already been able to display these registers in the 
same form.

OK for the trunk?

Thanks,
Yufeng

gas/

2013-02-27  Yufeng Zhang  <yufeng.zhang@arm.com>

	* config/tc-aarch64.c (parse_sys_reg): Allow the full range of CRn
	for system registers.

gas/testsuite/

2013-02-27  Yufeng Zhang  <yufeng.zhang@arm.com>

	* gas/aarch64/illegal.l: Delete the error message for
	msr S3_1_C13_C15_1,x7.
	* gas/aarch64/sysreg.s: Add new tests.
	* gas/aarch64/sysreg.d: Update.

diff --git a/gas/config/tc-aarch64.c b/gas/config/tc-aarch64.c
index 3d75968..543e90b 100644
--- a/gas/config/tc-aarch64.c
+++ b/gas/config/tc-aarch64.c
@@ -3197,10 +3197,14 @@ parse_sys_reg (char **str, struct hash_control *sys_regs, int imple_defined_p)
 	  unsigned int op0, op1, cn, cm, op2;
 	  if (sscanf (buf, "s%u_%u_c%u_c%u_%u", &op0, &op1, &cn, &cm, &op2) != 5)
 	    return PARSE_FAIL;
-	  /* Register access is encoded as follows:
+	  /* The architecture specifies the encoding space for implementation
+	     defined registers as:
 	     op0  op1  CRn   CRm   op2
-	     11   xxx  1x11  xxxx  xxx.  */
-	  if (op0 != 3 || op1 > 7 || (cn | 0x4) != 0xf || cm > 15 || op2 > 7)
+	     11   xxx  1x11  xxxx  xxx
+	     For convenience GAS accepts a wider encoding space, as follows:
+	     op0  op1  CRn   CRm   op2
+	     11   xxx  xxxx  xxxx  xxx  */
+	  if (op0 != 3 || op1 > 7 || cn > 15 || cm > 15 || op2 > 7)
 	    return PARSE_FAIL;
 	  value = (op0 << 14) | (op1 << 11) | (cn << 7) | (cm << 3) | op2;
 	}
diff --git a/gas/testsuite/gas/aarch64/illegal.l b/gas/testsuite/gas/aarch64/illegal.l
index 6905866..5bc9c3c 100644
--- a/gas/testsuite/gas/aarch64/illegal.l
+++ b/gas/testsuite/gas/aarch64/illegal.l
@@ -520,7 +520,6 @@
 [^:]*:496: Error: .*`str x1,page_table_count'
 [^:]*:498: Error: .*`prfm PLDL3KEEP,\[x9,x15,sxtx#2\]'
 [^:]*:500: Error: .*`mrs x5,S1_0_C13_C8_0'
-[^:]*:501: Error: .*`msr S3_1_C13_C15_1,x7'
 [^:]*:502: Error: .*`msr S3_1_C11_C15_-1,x7'
 [^:]*:503: Error: .*`msr S3_1_11_15_1,x7'
 [^:]*:506: Error: .*`movi w1,#15'
diff --git a/gas/testsuite/gas/aarch64/sysreg.d b/gas/testsuite/gas/aarch64/sysreg.d
index b83b270..c7cf00e 100644
--- a/gas/testsuite/gas/aarch64/sysreg.d
+++ b/gas/testsuite/gas/aarch64/sysreg.d
@@ -23,3 +23,6 @@ Disassembly of section \.text:
   3c:	d5380260 	mrs	x0, id_isar3_el1
   40:	d5380280 	mrs	x0, id_isar4_el1
   44:	d53802a0 	mrs	x0, id_isar5_el1
+  48:	d538cc00 	mrs	x0, s3_0_c12_c12_0
+  4c:	d5384600 	mrs	x0, s3_0_c4_c6_0
+  50:	d5184600 	msr	s3_0_c4_c6_0, x0
diff --git a/gas/testsuite/gas/aarch64/sysreg.s b/gas/testsuite/gas/aarch64/sysreg.s
index e6f770e..3287594 100644
--- a/gas/testsuite/gas/aarch64/sysreg.s
+++ b/gas/testsuite/gas/aarch64/sysreg.s
@@ -22,3 +22,7 @@
 	mrs x0, id_isar3_el1
 	mrs x0, id_isar4_el1
 	mrs x0, id_isar5_el1
+
+	mrs x0, s3_0_c12_c12_0
+	mrs x0, s3_0_c4_c6_0
+	msr s3_0_c4_c6_0, x0