/* tc-arm.c -- Assemble for the ARM
- Copyright (C) 1994, 95, 96, 97, 98, 1999, 2000
+ Copyright 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001
Free Software Foundation, Inc.
Contributed by Richard Earnshaw (rwe@pegasus.esprit.ec.org)
Modified by David Taylor (dtaylor@armltd.co.uk)
== inst.reloc.exp.X_add_number)
&& literals[lit_count].exp.X_unsigned == inst.reloc.exp.X_unsigned)
break;
+
+ if (literals[lit_count].exp.X_op == inst.reloc.exp.X_op
+ && inst.reloc.exp.X_op == O_symbol
+ && (literals[lit_count].exp.X_add_number
+ == inst.reloc.exp.X_add_number)
+ && (literals[lit_count].exp.X_add_symbol
+ == inst.reloc.exp.X_add_symbol)
+ && (literals[lit_count].exp.X_op_symbol
+ == inst.reloc.exp.X_op_symbol))
+ break;
+
lit_count++;
}
if (lit_count == next_literal_pool_place) /* New entry. */
{
- if (next_literal_pool_place > MAX_LITERAL_POOL_SIZE)
+ if (next_literal_pool_place >= MAX_LITERAL_POOL_SIZE)
{
inst.error = _("Literal Pool Overflow");
return FAIL;
return;
}
+#if 0 /* The first edition of the ARM architecture manual stated that
+ writing anything other than the flags with an immediate operation
+ had UNPREDICTABLE effects. This constraint was removed in the
+ second edition of the specification. */
if ((cpu_variant & ARM_EXT_V5) != ARM_EXT_V5
&& inst.instruction & ((PSR_c | PSR_x | PSR_s) << PSR_SHIFT))
{
inst.error = _("immediate value cannot be used to set this field");
return;
}
+#endif
flags |= INST_IMMEDIATE;
if (Rs != Rd)
{
- inst.error = _("dest and source1 one must be the same register");
+ inst.error = _("dest and source1 must be the same register");
return;
}
Rs = Rn;
}
/* Catch special cases. */
- if (cpu_variant != (FPU_DEFAULT | CPU_DEFAULT))
+ if (cpu_variant & ARM_EXT_XSCALE)
+ mach = bfd_mach_arm_XScale;
+ else if (cpu_variant & ARM_EXT_V5E)
+ mach = bfd_mach_arm_5TE;
+ else if (cpu_variant & ARM_EXT_V5)
+ {
+ if (cpu_variant & ARM_EXT_THUMB)
+ mach = bfd_mach_arm_5T;
+ else
+ mach = bfd_mach_arm_5;
+ }
+ else if (cpu_variant & ARM_EXT_HALFWORD)
{
- if (cpu_variant & ARM_EXT_XSCALE)
- mach = bfd_mach_arm_XScale;
- else if (cpu_variant & ARM_EXT_V5E)
- mach = bfd_mach_arm_5TE;
- else if (cpu_variant & ARM_EXT_V5)
- {
- if (cpu_variant & ARM_EXT_THUMB)
- mach = bfd_mach_arm_5T;
- else
- mach = bfd_mach_arm_5;
- }
- else if (cpu_variant & ARM_EXT_HALFWORD)
- {
- if (cpu_variant & ARM_EXT_THUMB)
- mach = bfd_mach_arm_4T;
- else
- mach = bfd_mach_arm_4;
- }
- else if (cpu_variant & ARM_EXT_LONGMUL)
- mach = bfd_mach_arm_3M;
+ if (cpu_variant & ARM_EXT_THUMB)
+ mach = bfd_mach_arm_4T;
+ else
+ mach = bfd_mach_arm_4;
}
+ else if (cpu_variant & ARM_EXT_LONGMUL)
+ mach = bfd_mach_arm_3M;
bfd_set_arch_mach (stdoutput, TARGET_ARCH, mach);
}
newval = (newval & 0xf800) | ((value & 0x7fffff) >> 12);
newval2 = (newval2 & 0xf800) | ((value & 0xfff) >> 1);
+ if (fixP->fx_r_type == BFD_RELOC_THUMB_PCREL_BLX)
+ /* Remove bit zero of the adjusted offset. Bit zero can only be
+ set if the upper insn is at a half-word boundary, since the
+ destination address, an ARM instruction, must always be on a
+ word boundary. The semantics of the BLX (1) instruction, however,
+ are that bit zero in the offset must always be zero, and the
+ corresponding bit one in the target address will be set from bit
+ one of the source address. */
+ newval2 &= ~1;
md_number_to_chars (buf, newval, THUMB_SIZE);
md_number_to_chars (buf + THUMB_SIZE, newval2, THUMB_SIZE);
}
ARM_SET_INTERWORK (sym, support_interwork);
#endif
- if (label_is_thumb_function_name)
+ /* Note - do not allow local symbols (.Lxxx) to be labeled
+ as Thumb functions. This is because these labels, whilst
+ they exist inside Thumb code, are not the entry points for
+ possible ARM->Thumb calls. Also, these labels can be used
+ as part of a computed goto or switch statement. eg gcc
+ can generate code that looks like this:
+
+ ldr r2, [pc, .Laaa]
+ lsl r3, r3, #2
+ ldr r2, [r3, r2]
+ mov pc, r2
+
+ .Lbbb: .word .Lxxx
+ .Lccc: .word .Lyyy
+ ..etc...
+ .Laaa: .word Lbbb
+
+ The first instruction loads the address of the jump table.
+ The second instruction converts a table index into a byte offset.
+ The third instruction gets the jump address out of the table.
+ The fourth instruction performs the jump.
+
+ If the address stored at .Laaa is that of a symbol which has the
+ Thumb_Func bit set, then the linker will arrange for this address
+ to have the bottom bit set, which in turn would mean that the
+ address computation performed by the third instruction would end
+ up with the bottom bit set. Since the ARM is capable of unaligned
+ word loads, the instruction would then load the incorrect address
+ out of the jump table, and chaos would ensue. */
+ if (label_is_thumb_function_name
+ && (S_GET_NAME (sym)[0] != '.' || S_GET_NAME (sym)[1] != 'L')
+ && (bfd_get_section_flags (stdoutput, now_seg) & SEC_CODE) != 0)
{
/* When the address of a Thumb function is taken the bottom
bit of that address should be set. This will allow
}
#endif /* OBJ_ELF */
+
+/* This is called from HANDLE_ALIGN in write.c. Fill in the contents
+ of an rs_align_code fragment. */
+
+void
+arm_handle_align (fragP)
+ fragS *fragP;
+{
+ static char const arm_noop[4] = { 0x00, 0x00, 0xa0, 0xe1 };
+ static char const thumb_noop[2] = { 0xc0, 0x46 };
+ static char const arm_bigend_noop[4] = { 0xe1, 0xa0, 0x00, 0x00 };
+ static char const thumb_bigend_noop[2] = { 0x46, 0xc0 };
+
+ int bytes, fix, noop_size;
+ char * p;
+ const char * noop;
+
+ if (fragP->fr_type != rs_align_code)
+ return;
+
+ bytes = fragP->fr_next->fr_address - fragP->fr_address - fragP->fr_fix;
+ p = fragP->fr_literal + fragP->fr_fix;
+ fix = 0;
+
+ if (bytes > MAX_MEM_FOR_RS_ALIGN_CODE)
+ bytes &= MAX_MEM_FOR_RS_ALIGN_CODE;
+
+ if (fragP->tc_frag_data)
+ {
+ if (target_big_endian)
+ noop = thumb_bigend_noop;
+ else
+ noop = thumb_noop;
+ noop_size = sizeof (thumb_noop);
+ }
+ else
+ {
+ if (target_big_endian)
+ noop = arm_bigend_noop;
+ else
+ noop = arm_noop;
+ noop_size = sizeof (arm_noop);
+ }
+
+ if (bytes & (noop_size - 1))
+ {
+ fix = bytes & (noop_size - 1);
+ memset (p, 0, fix);
+ p += fix;
+ bytes -= fix;
+ }
+
+ while (bytes >= noop_size)
+ {
+ memcpy (p, noop, noop_size);
+ p += noop_size;
+ bytes -= noop_size;
+ fix += noop_size;
+ }
+
+ fragP->fr_fix += fix;
+ fragP->fr_var = noop_size;
+}
+
+/* Called from md_do_align. Used to create an alignment
+ frag in a code section. */
+
+void
+arm_frag_align_code (n, max)
+ int n;
+ int max;
+{
+ char * p;
+
+ /* We assume that there will never be a requirment
+ to support alignments greater than 32 bytes. */
+ if (max > MAX_MEM_FOR_RS_ALIGN_CODE)
+ as_fatal (_("alignments greater than 32 bytes not supported in .text sections."));
+
+ p = frag_var (rs_align_code,
+ MAX_MEM_FOR_RS_ALIGN_CODE,
+ 1,
+ (relax_substateT) max,
+ (symbolS *) NULL,
+ (offsetT) n,
+ (char *) NULL);
+ *p = 0;
+
+}
+
+/* Perform target specific initialisation of a frag. */
+
+void
+arm_init_frag (fragP)
+ fragS *fragP;
+{
+ /* Record whether this frag is in an ARM or a THUMB area. */
+ fragP->tc_frag_data = thumb_mode;
+}
projects / external / binutils.git / blobdiff