This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
PATCH: fix float handling in pdp11 backend
- From: Paul Koning <pkoning at equallogic dot com>
- To: gcc-patches at gcc dot gnu dot org
- Date: Tue, 3 Feb 2004 12:36:10 -0500
- Subject: PATCH: fix float handling in pdp11 backend
This patch fixes the pdp11 back end to handle float values correctly.
Committed.
paul
2004-02-03 Paul Koning <pkoning@equallogic.com>
* config/pdp11/pdp11-modes.def: Add RESET_FLOAT_FORMAT calls.
* config/pdp11/pdp11-protos.h (legitimate_const_double_p): Add.
* config/pdp11/pdp11.c (encode_pdp11_f, decode_pdp11_f,
encode_pdp11_d, decode_pdp11_d): New functions to handle PDP11
floating point format.
(pdp11_f_format, pdp11_d_format): New real_format descriptors for
the above functions.
(output_move_quad): Output float values in correct target format.
(legitimate_const_double_p): New function.
* config/pdp11/pdp11.h: Fix typos.
(FLOAT_WORDS_BIG_ENDIAN): Add definition.
(TARGET_FLOAT_FORMAT): Ditto.
(pdp11_f_format, pdp11_d_format): Add external declarations.
(MAX_REGS_PER_ADDRESS): Corrected.
(LEGITIMATE_CONSTANT_P): Use legitimate_const_double_p().
(PRINT_OPERAND): Output float literals in target format.
Index: pdp11-modes.def
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/pdp11/pdp11-modes.def,v
retrieving revision 1.3
diff -u -r1.3 pdp11-modes.def
--- pdp11-modes.def 13 Oct 2003 21:16:31 -0000 1.3
+++ pdp11-modes.def 3 Feb 2004 17:32:30 -0000
@@ -1,5 +1,5 @@
/* Definitions of target machine for GNU compiler, for the pdp-11
- Copyright (C) 2002 Free Software Foundation, Inc.
+ Copyright (C) 2002, 2004 Free Software Foundation, Inc.
Contributed by Michael K. Gschwind (mike@vlsivie.tuwien.ac.at).
This file is part of GCC.
@@ -23,3 +23,5 @@
CCFPmode is used for FPU, but should we use a separate reg? */
CC_MODE (CCFP);
+RESET_FLOAT_FORMAT (SF, pdp11_f_format);
+RESET_FLOAT_FORMAT (DF, pdp11_d_format);
Index: pdp11-protos.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/pdp11/pdp11-protos.h,v
retrieving revision 1.5
diff -u -r1.5 pdp11-protos.h
--- pdp11-protos.h 28 Sep 2003 12:09:07 -0000 1.5
+++ pdp11-protos.h 3 Feb 2004 17:32:30 -0000
@@ -1,5 +1,5 @@
/* Definitions of target machine for GNU compiler, for the pdp-11
- Copyright (C) 2000, 2003 Free Software Foundation, Inc.
+ Copyright (C) 2000, 2003, 2004 Free Software Foundation, Inc.
Contributed by Michael K. Gschwind (mike@vlsivie.tuwien.ac.at).
This file is part of GCC.
@@ -29,6 +29,7 @@
extern int comp_operator (rtx, enum machine_mode);
extern int legitimate_address_p (enum machine_mode, rtx);
+extern int legitimate_const_double_p (rtx);
extern void notice_update_cc_on_set (rtx, rtx);
extern void output_addr_const_pdp11 (FILE *, rtx);
extern const char *output_move_double (rtx *);
Index: pdp11.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/pdp11/pdp11.c,v
retrieving revision 1.35
diff -u -r1.35 pdp11.c
--- pdp11.c 3 Feb 2004 06:43:54 -0000 1.35
+++ pdp11.c 3 Feb 2004 17:32:30 -0000
@@ -51,6 +51,90 @@
defined in tm.h */
int current_first_parm_offset;
+/* Routines to encode/decode pdp11 floats */
+static void encode_pdp11_f (const struct real_format *fmt,
+ long *, const REAL_VALUE_TYPE *);
+static void decode_pdp11_f (const struct real_format *,
+ REAL_VALUE_TYPE *, const long *);
+static void encode_pdp11_d (const struct real_format *fmt,
+ long *, const REAL_VALUE_TYPE *);
+static void decode_pdp11_d (const struct real_format *,
+ REAL_VALUE_TYPE *, const long *);
+
+/* These two are taken from the corresponding vax descriptors
+ in real.c, changing only the encode/decode routine pointers. */
+const struct real_format pdp11_f_format =
+ {
+ encode_pdp11_f,
+ decode_pdp11_f,
+ 2,
+ 1,
+ 24,
+ 24,
+ -127,
+ 127,
+ 15,
+ false,
+ false,
+ false,
+ false,
+ false
+ };
+
+const struct real_format pdp11_d_format =
+ {
+ encode_pdp11_d,
+ decode_pdp11_d,
+ 2,
+ 1,
+ 56,
+ 56,
+ -127,
+ 127,
+ 15,
+ false,
+ false,
+ false,
+ false,
+ false
+ };
+
+static void
+encode_pdp11_f (const struct real_format *fmt ATTRIBUTE_UNUSED, long *buf,
+ const REAL_VALUE_TYPE *r)
+{
+ (*vax_f_format.encode) (fmt, buf, r);
+ buf[0] = ((buf[0] >> 16) & 0xffff) | ((buf[0] & 0xffff) << 16);
+}
+
+static void
+decode_pdp11_f (const struct real_format *fmt ATTRIBUTE_UNUSED,
+ REAL_VALUE_TYPE *r, const long *buf)
+{
+ long tbuf;
+ tbuf = ((buf[0] >> 16) & 0xffff) | ((buf[0] & 0xffff) << 16);
+ (*vax_f_format.decode) (fmt, r, &tbuf);
+}
+
+static void
+encode_pdp11_d (const struct real_format *fmt ATTRIBUTE_UNUSED, long *buf,
+ const REAL_VALUE_TYPE *r)
+{
+ (*vax_d_format.encode) (fmt, buf, r);
+ buf[0] = ((buf[0] >> 16) & 0xffff) | ((buf[0] & 0xffff) << 16);
+ buf[1] = ((buf[1] >> 16) & 0xffff) | ((buf[1] & 0xffff) << 16);
+}
+
+static void
+decode_pdp11_d (const struct real_format *fmt ATTRIBUTE_UNUSED,
+ REAL_VALUE_TYPE *r, const long *buf)
+{
+ long tbuf[2];
+ tbuf[0] = ((buf[0] >> 16) & 0xffff) | ((buf[0] & 0xffff) << 16);
+ tbuf[1] = ((buf[1] >> 16) & 0xffff) | ((buf[1] & 0xffff) << 16);
+ (*vax_d_format.decode) (fmt, r, tbuf);
+}
+
/* This is where the condition code register lives. */
/* rtx cc0_reg_rtx; - no longer needed? */
@@ -683,22 +767,12 @@
{
if (GET_CODE (operands[1]) == CONST_DOUBLE)
{
- /* floats only. not yet supported!
-
- -- compute it into PDP float format, - internally,
- just use IEEE and ignore possible problems ;-)
-
- we might get away with it !!!! */
-
- abort();
-
-#ifndef HOST_WORDS_BIG_ENDIAN
- latehalf[1] = GEN_INT (CONST_DOUBLE_LOW (operands[1]));
- operands[1] = GEN_INT (CONST_DOUBLE_HIGH (operands[1]));
-#else /* HOST_WORDS_BIG_ENDIAN */
- latehalf[1] = GEN_INT (CONST_DOUBLE_HIGH (operands[1]));
- operands[1] = GEN_INT (CONST_DOUBLE_LOW (operands[1]));
-#endif /* HOST_WORDS_BIG_ENDIAN */
+ REAL_VALUE_TYPE r;
+ long dval[2];
+ REAL_VALUE_FROM_CONST_DOUBLE (r, operands[1]);
+ REAL_VALUE_TO_TARGET_DOUBLE (r, dval);
+ latehalf[1] = GEN_INT (dval[1]);
+ operands[1] = GEN_INT (dval[0]);
}
else if (GET_CODE(operands[1]) == CONST_INT)
{
@@ -1589,6 +1663,21 @@
return 1;
/* #undef REG_OK_STRICT */
+}
+
+/* This function checks whether a real value can be encoded as
+ a literal, i.e., addressing mode 27. In that mode, real values
+ are one word values, so the remaining 48 bits have to be zero. */
+int
+legitimate_const_double_p (rtx address)
+{
+ REAL_VALUE_TYPE r;
+ long sval[2];
+ REAL_VALUE_FROM_CONST_DOUBLE (r, address);
+ REAL_VALUE_TO_TARGET_DOUBLE (r, sval);
+ if ((sval[0] & 0xffff) == 0 && sval[1] == 0)
+ return 1;
+ return 0;
}
/* A copy of output_addr_const modified for pdp11 expression syntax.
Index: pdp11.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/pdp11/pdp11.h,v
retrieving revision 1.54
diff -u -r1.54 pdp11.h
--- pdp11.h 26 Jan 2004 18:17:58 -0000 1.54
+++ pdp11.h 3 Feb 2004 17:32:31 -0000
@@ -167,14 +167,27 @@
/* Define this if most significant byte of a word is the lowest numbered. */
#define BYTES_BIG_ENDIAN 0
-/* Define this if most significant word of a multiword number is numbered. */
+/* Define this if most significant word of a multiword number is first. */
#define WORDS_BIG_ENDIAN 1
+/* Define that floats are in VAX order, not high word first as for ints. */
+#define FLOAT_WORDS_BIG_ENDIAN 0
+
/* Width of a word, in units (bytes).
UNITS OR BYTES - seems like units */
#define UNITS_PER_WORD 2
+/* This machine doesn't use IEEE floats. */
+/* Because the pdp11 (at least Unix) convention for 32 bit ints is
+ big endian, opposite for what you need for float, the vax float
+ conversion routines aren't actually used directly. But the underlying
+ format is indeed the vax/pdp11 float format. */
+#define TARGET_FLOAT_FORMAT VAX_FLOAT_FORMAT
+
+extern const struct real_format pdp11_f_format;
+extern const struct real_format pdp11_d_format;
+
/* Maximum sized of reasonable data type
DImode or Dfmode ...*/
#define MAX_FIXED_MODE_SIZE 64
@@ -446,8 +459,8 @@
operand as its first argument and the constraint letter as its
second operand.
- `Q' is for memory references using take more than 1 instruction.
- `R' is for memory references which take 1 word for the instruction. */
+ `Q' is for memory references that require an extra word after the opcode.
+ `R' is for memory references which are encoded within the opcode. */
#define EXTRA_CONSTRAINT(OP,CODE) \
((GET_CODE (OP) != MEM) ? 0 \
@@ -678,7 +691,7 @@
/* Maximum number of registers that can appear in a valid memory address. */
-#define MAX_REGS_PER_ADDRESS 2
+#define MAX_REGS_PER_ADDRESS 1
/* Recognize any constant value that is a valid address. */
@@ -687,7 +700,8 @@
/* Nonzero if the constant value X is a legitimate general operand.
It is given that X satisfies CONSTANT_P or is a CONST_DOUBLE. */
-#define LEGITIMATE_CONSTANT_P(X) (TARGET_FPU? 1: !(GET_CODE(X) == CONST_DOUBLE))
+#define LEGITIMATE_CONSTANT_P(X) \
+ (GET_CODE (X) != CONST_DOUBLE || legitimate_const_double_p (X))
/* The macros REG_OK_FOR..._P assume that the arg is a REG rtx
and check its validity for a certain class.
@@ -1078,9 +1092,11 @@
else if (GET_CODE (X) == MEM) \
output_address (XEXP (X, 0)); \
else if (GET_CODE (X) == CONST_DOUBLE && GET_MODE (X) != SImode) \
- { char buf[30]; \
- real_to_decimal (buf, CONST_DOUBLE_REAL_VALUE (X), sizeof (buf), 0, 1); \
- fprintf (FILE, "$0F%s", buf); } \
+ { REAL_VALUE_TYPE r; \
+ long sval[2]; \
+ REAL_VALUE_FROM_CONST_DOUBLE (r, X); \
+ REAL_VALUE_TO_TARGET_DOUBLE (r, sval); \
+ fprintf (FILE, "$%#o", sval[0] >> 16); } \
else { putc ('$', FILE); output_addr_const_pdp11 (FILE, X); }}
/* Print a memory address as an operand to reference that memory location. */