arm64: Fix nrm2 for input vectors with Inf

Fix double precision nrm2 kernels returning NaN when the
input vectors contain Inf/-Inf.

Author: ashwinyes

kernel/arm64/KERNEL.NEOVERSEN1

@@ -91,10 +91,10 @@ IDAMAXKERNEL   = iamax_thunderx2t99.c
 ICAMAXKERNEL   = izamax_thunderx2t99.c
 IZAMAXKERNEL   = izamax_thunderx2t99.c
 
-SNRM2KERNEL    = nrm2.S
-DNRM2KERNEL    = nrm2.S
-CNRM2KERNEL    = znrm2.S
-ZNRM2KERNEL    = znrm2.S
+SNRM2KERNEL    = scnrm2_thunderx2t99.c
+DNRM2KERNEL    = dznrm2_thunderx2t99.c
+CNRM2KERNEL    = scnrm2_thunderx2t99.c
+ZNRM2KERNEL    = dznrm2_thunderx2t99.c
 
 DDOTKERNEL     = dot_thunderx2t99.c
 SDOTKERNEL     = dot_thunderx2t99.c

kernel/arm64/KERNEL.THUNDERX2T99

@@ -153,12 +153,12 @@ IDAMAXKERNEL   = iamax_thunderx2t99.c
 ICAMAXKERNEL   = izamax_thunderx2t99.c
 IZAMAXKERNEL   = izamax_thunderx2t99.c
 
-SNRM2KERNEL    = nrm2.S
-CNRM2KERNEL    = nrm2.S
+SNRM2KERNEL    = scnrm2_thunderx2t99.c
+CNRM2KERNEL    = scnrm2_thunderx2t99.c
 #DNRM2KERNEL    = dznrm2_thunderx2t99_fast.c
 #ZNRM2KERNEL    = dznrm2_thunderx2t99_fast.c
-DNRM2KERNEL    = znrm2.S
-ZNRM2KERNEL    = znrm2.S
+DNRM2KERNEL    = dznrm2_thunderx2t99.c
+ZNRM2KERNEL    = dznrm2_thunderx2t99.c
 
 
 DDOTKERNEL     = dot_thunderx2t99.c

kernel/arm64/KERNEL.THUNDERX3T110

@@ -153,16 +153,13 @@ IDAMAXKERNEL   = iamax_thunderx2t99.c
 ICAMAXKERNEL   = izamax_thunderx2t99.c
 IZAMAXKERNEL   = izamax_thunderx2t99.c
 
-#SNRM2KERNEL    = scnrm2_thunderx2t99.c
-#CNRM2KERNEL    = scnrm2_thunderx2t99.c
-##DNRM2KERNEL    = dznrm2_thunderx2t99_fast.c
-##ZNRM2KERNEL    = dznrm2_thunderx2t99_fast.c
-#DNRM2KERNEL    = dznrm2_thunderx2t99.c
-#ZNRM2KERNEL    = dznrm2_thunderx2t99.c
-SNRM2KERNEL = nrm2.S
-DNRM2KERNEL = nrm2.S
-CNRM2KERNEL = znrm2.S
-ZNRM2KERNEL = znrm2.S
+SNRM2KERNEL    = scnrm2_thunderx2t99.c
+CNRM2KERNEL    = scnrm2_thunderx2t99.c
+#DNRM2KERNEL    = dznrm2_thunderx2t99_fast.c
+#ZNRM2KERNEL    = dznrm2_thunderx2t99_fast.c
+DNRM2KERNEL    = dznrm2_thunderx2t99.c
+ZNRM2KERNEL    = dznrm2_thunderx2t99.c
+
 
 DDOTKERNEL     = dot_thunderx2t99.c
 SDOTKERNEL     = dot_thunderx2t99.c

kernel/arm64/dznrm2_thunderx2t99.c

@@ -58,6 +58,7 @@ extern int blas_level1_thread_with_return_value(int mode, BLASLONG m, BLASLONG n
 #define CUR_MAXINV	"d8"
 #define CUR_MAXINV_V	"v8.2d"
 #define CUR_MAX_V	"v8.2d"
+#define REGINF		"d9"
 
 static void nrm2_compute(BLASLONG n, FLOAT *x, BLASLONG inc_x,
 		         double *ssq, double *scale)
@@ -79,8 +80,10 @@ static void nrm2_compute(BLASLONG n, FLOAT *x, BLASLONG inc_x,
 	"	ble	9f //nrm2_kernel_L999			\n"
 
 	"1: //nrm2_kernel_F_BEGIN:				\n"
+	"	mov	x6, #0x7FF0000000000000 //+Infinity	\n"
 	"	fmov	"REGZERO", xzr				\n"
 	"	fmov	"REGONE", #1.0				\n"
+	"	fmov	"REGINF", x6				\n"
 	"	lsl	"INC_X", "INC_X", #"INC_SHIFT"		\n"
 	"	mov	"J", "N"				\n"
 	"	cmp	"J", xzr				\n"
@@ -104,6 +107,8 @@ static void nrm2_compute(BLASLONG n, FLOAT *x, BLASLONG inc_x,
 	"	ldr	d4, ["X"]				\n"
 	"	fabs	d4, d4					\n"
 	"	fmax	"CUR_MAX", "SCALE", d4			\n"
+	"	fcmp	"CUR_MAX", "REGINF"			\n"
+	"	beq	10f					\n"
 	"	fdiv	"SCALE", "SCALE", "CUR_MAX"		\n"
 	"	fmul	"SCALE", "SCALE", "SCALE"		\n"
 	"	fmul	"SSQ", "SSQ", "SCALE"			\n"
@@ -116,6 +121,8 @@ static void nrm2_compute(BLASLONG n, FLOAT *x, BLASLONG inc_x,
 	"	ldr	d3, ["X", #8]				\n"
 	"	fabs	d3, d3					\n"
 	"	fmax	"CUR_MAX", "SCALE", d3			\n"
+	"	fcmp	"CUR_MAX", "REGINF"			\n"
+	"	beq	10f					\n"
 	"	fdiv	"SCALE", "SCALE", "CUR_MAX"		\n"
 	"	fmul	"SCALE", "SCALE", "SCALE"		\n"
 	"	fmul	"SSQ", "SSQ", "SCALE"			\n"
@@ -158,6 +165,8 @@ static void nrm2_compute(BLASLONG n, FLOAT *x, BLASLONG inc_x,
 	"	fmaxp	v24.2d, v24.2d, v26.2d			\n"
 	"	fmaxp	v24.2d, v24.2d, v24.2d			\n"
 	"	fmax	"CUR_MAX", "SCALE", d24			\n"
+	"	fcmp	"CUR_MAX", "REGINF"			\n"
+	"	beq	10f					\n"
 	"	fdiv	"CUR_MAXINV", "REGONE", "CUR_MAX"	\n"
 	"	//dup	"CUR_MAX_V", v7.d[0]			\n"
 	"	fdiv	"SCALE", "SCALE", "CUR_MAX"		\n"
@@ -217,6 +226,8 @@ static void nrm2_compute(BLASLONG n, FLOAT *x, BLASLONG inc_x,
 	"	fmaxp	v24.2d, v24.2d, v26.2d			\n"
 	"	fmaxp	v24.2d, v24.2d, v24.2d			\n"
 	"	fmax	"CUR_MAX", "SCALE", d24			\n"
+	"	fcmp	"CUR_MAX", "REGINF"			\n"
+	"	beq	10f					\n"
 	"	fdiv	"CUR_MAXINV", "REGONE", "CUR_MAX"	\n"
 	"	//dup	"CUR_MAX_V", v7.d[0]			\n"
 	"	fdiv	"SCALE", "SCALE", "CUR_MAX"		\n"
@@ -265,6 +276,8 @@ static void nrm2_compute(BLASLONG n, FLOAT *x, BLASLONG inc_x,
 	"	ldr	d4, ["X"]				\n"
 	"	fabs	d4, d4					\n"
 	"	fmax	"CUR_MAX", "SCALE", d4			\n"
+	"	fcmp	"CUR_MAX", "REGINF"			\n"
+	"	beq	10f					\n"
 	"	fdiv	"SCALE", "SCALE", "CUR_MAX"		\n"
 	"	fmul	"SCALE", "SCALE", "SCALE"		\n"
 	"	fmul	"SSQ", "SSQ", "SCALE"			\n"
@@ -276,6 +289,8 @@ static void nrm2_compute(BLASLONG n, FLOAT *x, BLASLONG inc_x,
 	"	ldr	d3, ["X", #8]				\n"
 	"	fabs	d3, d3					\n"
 	"	fmax	"CUR_MAX", "SCALE", d3			\n"
+	"	fcmp	"CUR_MAX", "REGINF"			\n"
+	"	beq	10f					\n"
 	"	fdiv	"SCALE", "SCALE", "CUR_MAX"		\n"
 	"	fmul	"SCALE", "SCALE", "SCALE"		\n"
 	"	fmul	"SSQ", "SSQ", "SCALE"			\n"
@@ -291,6 +306,11 @@ static void nrm2_compute(BLASLONG n, FLOAT *x, BLASLONG inc_x,
 	"9: //nrm2_kernel_L999:					\n"
 	"	str	"SSQ", [%[SSQ_]]			\n"
 	"	str	"SCALE", [%[SCALE_]]			\n"
+	"	b	11f					\n"
+	"10:							\n"
+	"	str	"REGINF", [%[SSQ_]]			\n"
+	"	str	"REGINF", [%[SCALE_]]			\n"
+	"11:							\n"
 
 	:
 	: [SSQ_]    "r"  (ssq),			//%0
@@ -300,7 +320,7 @@ static void nrm2_compute(BLASLONG n, FLOAT *x, BLASLONG inc_x,
 	  [INCX_]   "r"  (inc_x)		//%4
 	: "cc",
 	  "memory",
-	  "x0", "x1", "x2", "x3", "x4", "x5",
+	  "x0", "x1", "x2", "x3", "x4", "x5", "x6",
 	  "d0", "d1", "d2", "d3", "d4", "d5", "d6", "d7", "d8"
 	);
 
@@ -359,6 +379,12 @@ FLOAT CNAME(BLASLONG n, FLOAT *x, BLASLONG inc_x)
 			cur_ssq = *ptr;
 			cur_scale = *(ptr + 1);
 
+			if (cur_ssq == INFINITY) {
+				ssq = INFINITY;
+				scale = INFINITY;
+				break;
+			}
+
 			if (cur_scale != 0) {
 				if (cur_scale > scale) {
 					scale = (scale / cur_scale);