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authorMatthew Malcomson <matthew.malcomson@arm.com>2019-11-07 17:07:32 +0000
committerMatthew Malcomson <matthew.malcomson@arm.com>2019-11-07 17:07:32 +0000
commiteb5bbc482128b08d2ee8a2470951a74d8351146f (patch)
treeb528a83fba70f26f1c1669cbb3c6a1a107006622
parent[Patch][binutils][arm] .bfloat16 directive for Arm [6/X] (diff)
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[Patch][binutils][aarch64] .bfloat16 directive for AArch64 [7/10]
Hi, This patch is part of a series that adds support for Armv8.6-A (Matrix Multiply and BFloat16 extensions) to binutils. This patch implements the '.bfloat' directive for the AArch64 backend. The syntax for the directive is: .bfloat16 <0-n numbers> e.g. .bfloat16 12.0 .bfloat16 0.123, 1.0, NaN, 5 This is implemented by utilizing the ieee_atof_detail function in order to encode the slightly different bfloat16 format. Added testcases to verify the correct encoding for various bfloat16 values (NaN, Infinity (+ & -), normals, subnormals etc...). Cross compiled and tested on aarch64-none-elf and aarch64-none-linux-gnu with no issues. Committed on behalf of Mihail Ionescu. gas/ChangeLog: 2019-10-29 Mihail Ionescu <mihail.ionescu@arm.com> 2019-10-29 Barnaby Wilks <barnaby.wilks@arm.com> * config/tc-aarch64.c (md_atof): Add encoding for the bfloat16 format. * testsuite/gas/aarch64/bfloat16-directive-le.d: New test. * testsuite/gas/aarch64/bfloat16-directive-be.d: New test. * testsuite/gas/aarch64/bfloat16-directive.s: New test. Is it ok for trunk? Regards, Mihail
-rw-r--r--gas/ChangeLog8
-rw-r--r--gas/config/tc-aarch64.c49
-rw-r--r--gas/testsuite/gas/aarch64/bfloat16-directive-be.d11
-rw-r--r--gas/testsuite/gas/aarch64/bfloat16-directive-le.d11
-rw-r--r--gas/testsuite/gas/aarch64/bfloat16-directive.s19
5 files changed, 98 insertions, 0 deletions
diff --git a/gas/ChangeLog b/gas/ChangeLog
index ce2bfdc0d35..97054cc3f42 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,6 +1,14 @@
2019-11-07 Mihail Ionescu <mihail.ionescu@arm.com>
2019-11-07 Barnaby Wilks <barnaby.wilks@arm.com>
+ * config/tc-aarch64.c (md_atof): Add encoding for the bfloat16 format.
+ * testsuite/gas/aarch64/bfloat16-directive-le.d: New test.
+ * testsuite/gas/aarch64/bfloat16-directive-be.d: New test.
+ * testsuite/gas/aarch64/bfloat16-directive.s: New test.
+
+2019-11-07 Mihail Ionescu <mihail.ionescu@arm.com>
+2019-11-07 Barnaby Wilks <barnaby.wilks@arm.com>
+
* config/tc-arm.c (md_atof): Add encoding for bfloat16
* testsuite/gas/arm/bfloat16-directive-le.d: New test.
* testsuite/gas/arm/bfloat16-directive-be.d: New test.
diff --git a/gas/config/tc-aarch64.c b/gas/config/tc-aarch64.c
index 527d8590ca7..eea863b9a43 100644
--- a/gas/config/tc-aarch64.c
+++ b/gas/config/tc-aarch64.c
@@ -635,6 +635,54 @@ my_get_expression (expressionS * ep, char **str, int prefix_mode,
const char *
md_atof (int type, char *litP, int *sizeP)
{
+ /* If this is a bfloat16 type, then parse it slightly differently -
+ as it does not follow the IEEE standard exactly. */
+ if (type == 'b')
+ {
+ char * t;
+ LITTLENUM_TYPE words[MAX_LITTLENUMS];
+ FLONUM_TYPE generic_float;
+
+ t = atof_ieee_detail (input_line_pointer, 1, 8, words, &generic_float);
+
+ if (t)
+ input_line_pointer = t;
+ else
+ return _("invalid floating point number");
+
+ switch (generic_float.sign)
+ {
+ /* Is +Inf. */
+ case 'P':
+ words[0] = 0x7f80;
+ break;
+
+ /* Is -Inf. */
+ case 'N':
+ words[0] = 0xff80;
+ break;
+
+ /* Is NaN. */
+ /* bfloat16 has two types of NaN - quiet and signalling.
+ Quiet NaN has bit[6] == 1 && faction != 0, whereas
+ signalling Nan's have bit[0] == 0 && fraction != 0.
+ Chose this specific encoding as it is the same form
+ as used by other IEEE 754 encodings in GAS. */
+ case 0:
+ words[0] = 0x7fff;
+ break;
+
+ default:
+ break;
+ }
+
+ *sizeP = 2;
+
+ md_number_to_chars (litP, (valueT) words[0], sizeof (LITTLENUM_TYPE));
+
+ return NULL;
+ }
+
return ieee_md_atof (type, litP, sizeP, target_big_endian);
}
@@ -2107,6 +2155,7 @@ const pseudo_typeS md_pseudo_table[] = {
{"variant_pcs", s_variant_pcs, 0},
#endif
{"float16", float_cons, 'h'},
+ {"bfloat16", float_cons, 'b'},
{0, 0, 0}
};
diff --git a/gas/testsuite/gas/aarch64/bfloat16-directive-be.d b/gas/testsuite/gas/aarch64/bfloat16-directive-be.d
new file mode 100644
index 00000000000..132d04e44fa
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/bfloat16-directive-be.d
@@ -0,0 +1,11 @@
+# name: Big endian bfloat16 literal directives
+# source: bfloat16-directive.s
+# as: -mbig-endian
+# objdump: -s --section=.data
+
+.*: +file format .*
+
+Contents of section \.data:
+ 0000 41403dfc 000042f7 8000c2f7 7fff7f80 .*
+ 0010 ff807f7f ff7f0080 80800001 8001007f .*
+ 0020 807f3f80 bf804000 c000 .*
diff --git a/gas/testsuite/gas/aarch64/bfloat16-directive-le.d b/gas/testsuite/gas/aarch64/bfloat16-directive-le.d
new file mode 100644
index 00000000000..f22d610d84b
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/bfloat16-directive-le.d
@@ -0,0 +1,11 @@
+# name: Little endian bfloat16 literal directives
+# source: bfloat16-directive.s
+# as: -mlittle-endian
+# objdump: -s --section=.data
+
+.*: +file format .*
+
+Contents of section \.data:
+ 0000 4041fc3d 0000f742 0080f7c2 ff7f807f .*
+ 0010 80ff7f7f 7fff8000 80800100 01807f00 .*
+ 0020 7f80803f 80bf0040 00c0 .*
diff --git a/gas/testsuite/gas/aarch64/bfloat16-directive.s b/gas/testsuite/gas/aarch64/bfloat16-directive.s
new file mode 100644
index 00000000000..66e17e4fc7d
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/bfloat16-directive.s
@@ -0,0 +1,19 @@
+.data
+ .bfloat16 12.0
+ .bfloat16 0.123
+ .bfloat16 +0.0
+ .bfloat16 123.4
+ .bfloat16 -0.0
+ .bfloat16 -123.4
+ .bfloat16 NaN
+ .bfloat16 Inf
+ .bfloat16 -Inf
+ .bfloat16 3.390e+38
+ .bfloat16 -3.390e+38
+ .bfloat16 1.175e-38
+ .bfloat16 -1.175e-38
+ .bfloat16 9.194e-41
+ .bfloat16 -9.194e-41
+ .bfloat16 1.167e-38
+ .bfloat16 -1.167e-38
+ .bfloat16 1.0, -1, 2.0, -2