[PATCH] flat loader v850 specific support abstracted

Architecture specific flat loader code for v850 moved into its
own v850 flat.h header. This patch also adds supporti for a number
of relocation cases that need to be handled at laod time.

Most of this code is originally from Miles Bader <miles@gnu.org>.

include/asm-v850/flat.h

 /*
  * include/asm-v850/flat.h -- uClinux flat-format executables
  *
- *  Copyright (C) 2002  NEC Corporation
- *  Copyright (C) 2002  Miles Bader <miles@gnu.org>
+ *  Copyright (C) 2002,03  NEC Electronics Corporation
+ *  Copyright (C) 2002,03  Miles Bader <miles@gnu.org>
  *
  * This file is subject to the terms and conditions of the GNU General
  * Public License.  See the file COPYING in the main directory of this
@@ -14,6 +14,117 @@
 #ifndef __V850_FLAT_H__
 #define __V850_FLAT_H__
 
+/* The amount by which a relocation can exceed the program image limits
+   without being regarded as an error.  On the v850, the relocations of
+   some base-pointers can be offset by 0x8000 (to allow better usage of the
+   space offered by 16-bit signed offsets -- in most cases the offsets used
+   with such a base-pointer will be negative).  */
+
+#define	flat_reloc_valid(reloc, size)	((reloc) <= (size + 0x8000))
+
+#define	flat_stack_align(sp)		/* nothing needed */
 #define	flat_argvp_envp_on_stack()	0
+#define	flat_old_ram_flag(flags)	(flags)
+
+/* We store the type of relocation in the top 4 bits of the `relval.' */
+
+/* Convert a relocation entry into an address.  */
+static inline unsigned long
+flat_get_relocate_addr (unsigned long relval)
+{
+	return relval & 0x0fffffff; /* Mask out top 4-bits */
+}
+
+#define flat_v850_get_reloc_type(relval) ((relval) >> 28)
+
+#define FLAT_V850_R_32		0 /* Normal 32-bit reloc */
+#define FLAT_V850_R_HI16S_LO15	1 /* High 16-bits + signed 15-bit low field */
+#define FLAT_V850_R_HI16S_LO16	2 /* High 16-bits + signed 16-bit low field */
+
+/* Extract the address to be relocated from the symbol reference at RP;
+   RELVAL is the raw relocation-table entry from which RP is derived.
+   For the v850, RP should always be half-word aligned.  */
+static inline unsigned long flat_get_addr_from_rp (unsigned long *rp,
+						   unsigned long relval)
+{
+	short *srp = (short *)rp;
+
+	switch (flat_v850_get_reloc_type (relval))
+	{
+	case FLAT_V850_R_32:
+		/* Simple 32-bit address.  */
+		return srp[0] | (srp[1] << 16);
+
+	case FLAT_V850_R_HI16S_LO16:
+		/* The high and low halves of the address are in the 16
+		   bits at RP, and the 2nd word of the 32-bit instruction
+		   following that, respectively.  The low half is _signed_
+		   so we have to sign-extend it and add it to the upper
+		   half instead of simply or-ing them together.
+
+		   Unlike most relocated address, this one is stored in
+		   native (little-endian) byte-order to avoid problems with
+		   trashing the low-order bit, so we have to convert to
+		   network-byte-order before returning, as that's what the
+		   caller expects.  */
+		return htonl ((srp[0] << 16) + srp[2]);
+
+	case FLAT_V850_R_HI16S_LO15:
+		/* The high and low halves of the address are in the 16
+		   bits at RP, and the upper 15 bits of the 2nd word of the
+		   32-bit instruction following that, respectively.  The
+		   low half is _signed_ so we have to sign-extend it and
+		   add it to the upper half instead of simply or-ing them
+		   together.  The lowest bit is always zero.
+
+		   Unlike most relocated address, this one is stored in
+		   native (little-endian) byte-order to avoid problems with
+		   trashing the low-order bit, so we have to convert to
+		   network-byte-order before returning, as that's what the
+		   caller expects.  */
+		return htonl ((srp[0] << 16) + (srp[2] & ~0x1));
+
+	default:
+		return ~0;	/* bogus value */
+	}
+}
+
+/* Insert the address ADDR into the symbol reference at RP;
+   RELVAL is the raw relocation-table entry from which RP is derived.
+   For the v850, RP should always be half-word aligned.  */
+static inline void flat_put_addr_at_rp (unsigned long *rp, unsigned long addr,
+					unsigned long relval)
+{
+	short *srp = (short *)rp;
+
+	switch (flat_v850_get_reloc_type (relval)) {
+	case FLAT_V850_R_32:
+		/* Simple 32-bit address.  */
+		srp[0] = addr & 0xFFFF;
+		srp[1] = (addr >> 16);
+		break;
+
+	case FLAT_V850_R_HI16S_LO16:
+		/* The high and low halves of the address are in the 16
+		   bits at RP, and the 2nd word of the 32-bit instruction
+		   following that, respectively.  The low half is _signed_
+		   so we must carry its sign bit to the upper half before
+		   writing the upper half.  */
+		srp[0] = (addr >> 16) + ((addr >> 15) & 0x1);
+		srp[2] = addr & 0xFFFF;
+		break;
+
+	case FLAT_V850_R_HI16S_LO15:
+		/* The high and low halves of the address are in the 16
+		   bits at RP, and the upper 15 bits of the 2nd word of the
+		   32-bit instruction following that, respectively.  The
+		   low half is _signed_ so we must carry its sign bit to
+		   the upper half before writing the upper half.  The
+		   lowest bit we preserve from the existing instruction.  */
+		srp[0] = (addr >> 16) + ((addr >> 15) & 0x1);
+		srp[2] = (addr & 0xFFFE) | (srp[2] & 0x1);
+		break;
+	}
+}
 
 #endif /* __V850_FLAT_H__ */