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[Patch, AArch64] Add support for hexadecimal-form floating-point immediate
- From: Yufeng Zhang <Yufeng dot Zhang at arm dot com>
- To: "binutils at sourceware dot org" <binutils at sourceware dot org>
- Cc: Richard Earnshaw <Richard dot Earnshaw at arm dot com>
- Date: Mon, 05 Nov 2012 19:19:39 +0000
- Subject: [Patch, AArch64] Add support for hexadecimal-form floating-point immediate
Hi,
This patch adds to the AArch64 GAS the support for the floating-point
immediate as a string beginning “0x” followed by the hexadecimal
representation of its IEEE754 encoding. This kind of fp immediate can
appear as the 2nd operand of any of the following instructions:
FMOV Sd, #fpimm
FMOV Dd, #fpimm
FMOV Vn.<T>, #fpimm
OK to commit?
Thanks,
Yufeng
include/opcode/
2012-11-05 Yufeng Zhang <yufeng.zhang@arm.com>
* aarch64.h (aarch64_get_sp_fp_enc): New function declaration.
(aarch64_get_dp_fp_enc): Ditto.
(aarch64_get_sp_fp_from_enc): Ditto.
(aarch64_get_dp_fp_from_enc): Ditto.
opcodes/
2012-11-05 Yufeng Zhang <yufeng.zhang@arm.com>
* aarch64-opc.c (aarch64_get_sp_fp_enc): New function.
(aarch64_get_dp_fp_enc): Ditto.
(aarch64_get_sp_fp_from_enc): Ditto.
(aarch64_get_dp_fp_from_enc): Ditto.
(aarch64_print_operand): Update.
gas/
2012-11-05 Yufeng Zhang <yufeng.zhang@arm.com>
* config/tc-aarch64.c (parse_aarch64_imm_float): Add parameter 'dp_p';
handle hexadecimal representation of IEEE754 encoding.
(parse_operands): Update the call to parse_aarch64_imm_float.
gas/testsuite/
2012-11-05 Yufeng Zhang <yufeng.zhang@arm.com>
* gas/aarch64/diagnostic.s: Add test.
* gas/aarch64/diagnostic.l: Update.
* gas/aarch64/illegal.s: Add test.
* gas/aarch64/illegal.l: Update.
* gas/aarch64/fpmov.s: New file.
* gas/aarch64/fpmov.d: New file.
diff --git a/gas/config/tc-aarch64.c b/gas/config/tc-aarch64.c
index e7a2fe0..824b3ec 100644
--- a/gas/config/tc-aarch64.c
+++ b/gas/config/tc-aarch64.c
@@ -2024,8 +2024,13 @@ encode_imm_float_bits (uint32_t imm)
| ((imm >> (31 - 7)) & 0x80); /* b[31] -> b[7] */
}
-/* Return TRUE if IMM is a valid floating-point immediate; return FALSE
- otherwise. */
+/* Return TRUE if the single-precision floating-point value encoded in IMM
+ can be expressed in the AArch64 8-bit signed floating-point format with
+ 3-bit exponent and normalized 4 bits of precision; in other words, the
+ floating-point value must be expressable as
+ (+/-) n / 16 * power (2, r)
+ where n and r are integers such that 16 <= n <=31 and -3 <= r <= 4. */
+
static bfd_boolean
aarch64_imm_float_p (uint32_t imm)
{
@@ -2043,30 +2048,65 @@ aarch64_imm_float_p (uint32_t imm)
&& ((imm & 0x7e000000) == e); /* bits 25-29 = ~ bit 30 */
}
-/* Note: this accepts the floating-point 0 constant. */
+/* Parse a floating-point immediate. Return TRUE on success and return the
+ value in *IMMED in the format of IEEE754 single-precision encoding.
+ *CCP points to the start of the string; DP_P is TRUE when the immediate
+ is expected to be in double-precision (N.B. this only matters when
+ hexadecimal representation is involved).
+
+ N.B. 0.0 is accepted by this function. */
+
static bfd_boolean
-parse_aarch64_imm_float (char **ccp, int *immed)
+parse_aarch64_imm_float (char **ccp, int *immed, bfd_boolean dp_p)
{
char *str = *ccp;
char *fpnum;
LITTLENUM_TYPE words[MAX_LITTLENUMS];
int found_fpchar = 0;
+ int64_t val = 0;
+ unsigned fpword = 0;
+ bfd_boolean hex_p = FALSE;
skip_past_char (&str, '#');
- /* We must not accidentally parse an integer as a floating-point number. Make
- sure that the value we parse is not an integer by checking for special
- characters '.' or 'e'.
- FIXME: This is a hack that is not very efficient, but doing better is
- tricky because type information isn't in a very usable state at parse
- time. */
fpnum = str;
skip_whitespace (fpnum);
if (strncmp (fpnum, "0x", 2) == 0)
- return FALSE;
+ {
+ /* Support the hexadecimal representation of the IEEE754 encoding.
+ Double-precision is expected when DP_P is TRUE, otherwise the
+ representation should be in single-precision. */
+ if (! parse_constant_immediate (&str, &val))
+ goto invalid_fp;
+
+ if (dp_p)
+ {
+ double d = aarch64_get_dp_fp_from_enc (val);
+
+ /* If the double-precision floating-point value cannot be expressed
+ in single-precision, it will not be expressable in our 8-bit
+ format. */
+ if ((double)(float) d != d)
+ goto invalid_fp;
+
+ fpword = aarch64_get_sp_fp_enc ((float) d);
+ }
+ else if ((uint64_t) val > 0xffffffff)
+ goto invalid_fp;
+ else
+ fpword = val;
+
+ hex_p = TRUE;
+ }
else
{
+ /* We must not accidentally parse an integer as a floating-point number.
+ Make sure that the value we parse is not an integer by checking for
+ special characters '.' or 'e'.
+ FIXME: This is a hack that is not very efficient, but doing better is
+ tricky because type information isn't in a very usable state at parse
+ time. */
for (; *fpnum != '\0' && *fpnum != ' ' && *fpnum != '\n'; fpnum++)
if (*fpnum == '.' || *fpnum == 'e' || *fpnum == 'E')
{
@@ -2078,25 +2118,25 @@ parse_aarch64_imm_float (char **ccp, int *immed)
return FALSE;
}
- if ((str = atof_ieee (str, 's', words)) != NULL)
+ if (! hex_p)
{
- unsigned fpword = 0;
int i;
+ if ((str = atof_ieee (str, 's', words)) == NULL)
+ goto invalid_fp;
+
/* Our FP word must be 32 bits (single-precision FP). */
for (i = 0; i < 32 / LITTLENUM_NUMBER_OF_BITS; i++)
{
fpword <<= LITTLENUM_NUMBER_OF_BITS;
fpword |= words[i];
}
+ }
- if (aarch64_imm_float_p (fpword) || (fpword & 0x7fffffff) == 0)
- *immed = fpword;
- else
- goto invalid_fp;
-
+ if (aarch64_imm_float_p (fpword) || (fpword & 0x7fffffff) == 0)
+ {
+ *immed = fpword;
*ccp = str;
-
return TRUE;
}
@@ -4717,7 +4757,7 @@ parse_operands (char *str, const aarch64_opcode *opcode)
bfd_boolean res1 = FALSE, res2 = FALSE;
/* N.B. -0.0 will be rejected; although -0.0 shouldn't be rejected,
it is probably not worth the effort to support it. */
- if (!(res1 = parse_aarch64_imm_float (&str, &qfloat))
+ if (!(res1 = parse_aarch64_imm_float (&str, &qfloat, FALSE))
&& !(res2 = parse_constant_immediate (&str, &val)))
goto failure;
if ((res1 && qfloat == 0) || (res2 && val == 0))
@@ -4778,7 +4818,10 @@ parse_operands (char *str, const aarch64_opcode *opcode)
case AARCH64_OPND_SIMD_FPIMM:
{
int qfloat;
- if (! parse_aarch64_imm_float (&str, &qfloat))
+ bfd_boolean dp_p =
+ (aarch64_get_qualifier_esize (inst.base.operands[0].qualifier)
+ == 8);
+ if (! parse_aarch64_imm_float (&str, &qfloat, dp_p))
goto failure;
if (qfloat == 0)
{
diff --git a/gas/testsuite/gas/aarch64/diagnostic.l b/gas/testsuite/gas/aarch64/diagnostic.l
index 714a2f0..2553548 100644
--- a/gas/testsuite/gas/aarch64/diagnostic.l
+++ b/gas/testsuite/gas/aarch64/diagnostic.l
@@ -85,3 +85,4 @@
[^:]*:87: Error: immediate offset out of range -256 to 252 at operand 3 -- `ldnp w7,w15,\[x3,#256\]'
[^:]*:88: Error: shift is not permitted at operand 2 -- `movi v1.2d,4294967295,lsl#0'
[^:]*:89: Error: shift amount non-zero at operand 2 -- `movi v1.8b,97,lsl#8'
+[^:]*:90: Error: invalid floating-point constant at operand 2 -- `fmov s0,0x42000000'
diff --git a/gas/testsuite/gas/aarch64/diagnostic.s b/gas/testsuite/gas/aarch64/diagnostic.s
index 2b1c01c..0b34662 100644
--- a/gas/testsuite/gas/aarch64/diagnostic.s
+++ b/gas/testsuite/gas/aarch64/diagnostic.s
@@ -87,3 +87,4 @@
ldnp w7, w15, [x3, #256]
movi v1.2d, 4294967295, lsl #0
movi v1.8b, 97, lsl #8
+ fmov s0, 0x42000000
diff --git a/gas/testsuite/gas/aarch64/fpmov.d b/gas/testsuite/gas/aarch64/fpmov.d
new file mode 100644
index 0000000..6afb3c5
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/fpmov.d
@@ -0,0 +1,19 @@
+#objdump: -dr
+
+.*: file format .*
+
+Disassembly of section .*:
+
+0000000000000000 <.*>:
+ 0: 1e251000 fmov s0, #1\.200000000000000000e\+01
+ 4: 1e251000 fmov s0, #1\.200000000000000000e\+01
+ 8: 1e251000 fmov s0, #1\.200000000000000000e\+01
+ c: 1e351000 fmov s0, #-1\.200000000000000000e\+01
+ 10: 1e351000 fmov s0, #-1\.200000000000000000e\+01
+ 14: 1e351000 fmov s0, #-1\.200000000000000000e\+01
+ 18: 1e751000 fmov d0, #-1\.200000000000000000e\+01
+ 1c: 1e751000 fmov d0, #-1\.200000000000000000e\+01
+ 20: 1e751000 fmov d0, #-1\.200000000000000000e\+01
+ 24: 1e69f000 fmov d0, #2\.421875000000000000e-01
+ 28: 1e69f000 fmov d0, #2\.421875000000000000e-01
+ 2c: 1e29f000 fmov s0, #2\.421875000000000000e-01
diff --git a/gas/testsuite/gas/aarch64/fpmov.s b/gas/testsuite/gas/aarch64/fpmov.s
new file mode 100644
index 0000000..ffc9881
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/fpmov.s
@@ -0,0 +1,17 @@
+// fpmov.s Test file for AArch64 floating-point move instructions.
+
+ .text
+
+ // fp mov immediate
+ fmov s0, 12.0
+ fmov s0, 1.2e1
+ fmov s0, 0x41400000
+ fmov s0, -12.0
+ fmov s0, -1.2e1
+ fmov s0, 0xc1400000
+ fmov d0, -12.0
+ fmov d0, -1.2e1
+ fmov d0, 0xC028000000000000
+ fmov d0, 0.2421875
+ fmov d0, 0x3fcf000000000000
+ fmov s0, 0x3e780000
diff --git a/gas/testsuite/gas/aarch64/illegal.l b/gas/testsuite/gas/aarch64/illegal.l
index 6c741cf..e17a1de 100644
--- a/gas/testsuite/gas/aarch64/illegal.l
+++ b/gas/testsuite/gas/aarch64/illegal.l
@@ -549,3 +549,6 @@
[^:]*:538: Error: .*`mov x0,##5'
[^:]*:540: Error: .*`msr daifset,x0'
[^:]*:541: Error: .*`msr daifclr,x0'
+[^:]*:543: Error: .*`fmov s0,#0x11'
+[^:]*:544: Error: .*`fmov s0,#0xC0280000C1400000'
+[^:]*:545: Error: .*`fmov d0,#0xC02f800000000000'
diff --git a/gas/testsuite/gas/aarch64/illegal.s b/gas/testsuite/gas/aarch64/illegal.s
index 9a12463..8b78181 100644
--- a/gas/testsuite/gas/aarch64/illegal.s
+++ b/gas/testsuite/gas/aarch64/illegal.s
@@ -539,3 +539,7 @@
msr daifset, x0
msr daifclr, x0
+
+ fmov s0, #0x11
+ fmov s0, #0xC0280000C1400000
+ fmov d0, #0xC02f800000000000
diff --git a/include/opcode/aarch64.h b/include/opcode/aarch64.h
index 3a26199..01fb71b 100644
--- a/include/opcode/aarch64.h
+++ b/include/opcode/aarch64.h
@@ -886,8 +886,20 @@ aarch64_num_of_operands (const aarch64_opcode *);
extern int
aarch64_stack_pointer_p (const aarch64_opnd_info *);
-extern
-int aarch64_zero_register_p (const aarch64_opnd_info *);
+extern int
+aarch64_zero_register_p (const aarch64_opnd_info *);
+
+extern uint32_t
+aarch64_get_sp_fp_enc (float);
+
+extern uint64_t
+aarch64_get_dp_fp_enc (double);
+
+extern float
+aarch64_get_sp_fp_from_enc (uint32_t);
+
+extern double
+aarch64_get_dp_fp_from_enc (uint64_t);
/* Given an operand qualifier, return the expected data element size
of a qualified operand. */
diff --git a/opcodes/aarch64-opc.c b/opcodes/aarch64-opc.c
index b5e0984..468fb9c 100644
--- a/opcodes/aarch64-opc.c
+++ b/opcodes/aarch64-opc.c
@@ -2111,7 +2111,7 @@ get_64bit_int_reg_name (int regno, int sp_reg_p)
return int_reg[has_zr][1][regno];
}
-/* Types for expanding an encoded 8-bit value to a floating-point value. */
+/* Types for conversion between floating-point value and its encoding. */
typedef union
{
@@ -2125,6 +2125,44 @@ typedef union
float f;
} single_conv_t;
+/* Utility functions for the conversion. */
+
+uint64_t
+aarch64_get_dp_fp_enc (double val)
+{
+ double_conv_t dc;
+
+ dc.d = val;
+ return dc.i;
+}
+
+double
+aarch64_get_dp_fp_from_enc (uint64_t val)
+{
+ double_conv_t dc;
+
+ dc.i = val;
+ return dc.d;
+}
+
+uint32_t
+aarch64_get_sp_fp_enc (float val)
+{
+ single_conv_t sc;
+
+ sc.f = val;
+ return sc.i;
+}
+
+float
+aarch64_get_sp_fp_from_enc (uint32_t val)
+{
+ single_conv_t sc;
+
+ sc.i = val;
+ return sc.f;
+}
+
/* IMM8 is an 8-bit floating-point constant with sign, 3-bit exponent and
normalized 4 bits of precision, encoded in "a:b:c:d:e:f:g:h" or FLD_imm8
(depending on the type of the instruction). IMM8 will be expanded to a
@@ -2468,16 +2506,14 @@ aarch64_print_operand (char *buf, size_t size, bfd_vma pc,
{
case 4: /* e.g. FMOV <Vd>.4S, #<imm>. */
{
- single_conv_t c;
- c.i = expand_fp_imm (0, opnd->imm.value);
- snprintf (buf, size, "#%.18e", c.f);
+ uint32_t val = expand_fp_imm (0, opnd->imm.value);
+ snprintf (buf, size, "#%.18e", aarch64_get_sp_fp_from_enc (val));
}
break;
- case 8: /* e.g. FMOV <Sd>, #<imm>. */
+ case 8: /* e.g. FMOV <Dd>, #<imm>. */
{
- double_conv_t c;
- c.i = expand_fp_imm (1, opnd->imm.value);
- snprintf (buf, size, "#%.18e", c.d);
+ uint64_t val = expand_fp_imm (1, opnd->imm.value);
+ snprintf (buf, size, "#%.18e", aarch64_get_dp_fp_from_enc (val));
}
break;
default: assert (0);