2000-04-07 Scott Bambrough <scottb@netwinder.org>

	* ChangeLog: Correct date on last entry.
	* arm-linux-tdep.c (arm_linux_push_arguments): New function.
	* config/arm/tm-linux: Redefined PUSH_ARGUMENTS for Linux.
	* config/arm/tm-embed: Fix build warning from redefinition of
	LOWEST_PC.
	* config/arm/tm-arm.h: Remove TARGET_BYTE_ORDER_SELECTABLE.
	* config/arm/tm-wince.h: Remove TARGET_BYTE_ORDER_SELECTABLE and
	TARGET_BYTE_ORDER.  Add TARGET_BYTE_ORDER_SELECTABLE_P to
	override default in tm-arm.h.  Use default target byte order
	from tm-arm.h.

1 files changed, 145 insertions, 0 deletions

diff --git a/gdb/arm-linux-tdep.c b/gdb/arm-linux-tdep.c
index bf26300ff03..8a575a4ff49 100644
--- a/gdb/arm-linux-tdep.c
+++ b/gdb/arm-linux-tdep.c
@@ -22,6 +22,7 @@
 #include "target.h"
 #include "value.h"
 #include "gdbtypes.h"
+#include "floatformat.h"
 
 #ifdef GET_LONGJMP_TARGET
 
@@ -76,6 +77,150 @@ arm_linux_extract_return_value (struct type *type,
   memcpy (valbuf, &regbuf[REGISTER_BYTE (regnum)], TYPE_LENGTH (type));
 }
 
+/* Note: ScottB
+
+   This function does not support passing parameters using the FPA
+   variant of the APCS.  It passes any floating point arguments in the
+   general registers and/or on the stack.
+   
+   FIXME:  This and arm_push_arguments should be merged.  However this 
+   	   function breaks on a little endian host, big endian target
+   	   using the COFF file format.  ELF is ok.  
+   	   
+   	   ScottB.  */
+   	   
+/* Addresses for calling Thumb functions have the bit 0 set.
+   Here are some macros to test, set, or clear bit 0 of addresses.  */
+#define IS_THUMB_ADDR(addr)	((addr) & 1)
+#define MAKE_THUMB_ADDR(addr)	((addr) | 1)
+#define UNMAKE_THUMB_ADDR(addr) ((addr) & ~1)
+   	  
+CORE_ADDR
+arm_linux_push_arguments (int nargs, value_ptr * args, CORE_ADDR sp,
+		          int struct_return, CORE_ADDR struct_addr)
+{
+  char *fp;
+  int argnum, argreg, nstack_size;
+
+  /* Walk through the list of args and determine how large a temporary
+     stack is required.  Need to take care here as structs may be
+     passed on the stack, and we have to to push them.  */
+  nstack_size = -4 * REGISTER_SIZE;	/* Some arguments go into A1-A4.  */
+
+  if (struct_return)			/* The struct address goes in A1.  */
+    nstack_size += REGISTER_SIZE;
+
+  /* Walk through the arguments and add their size to nstack_size.  */
+  for (argnum = 0; argnum < nargs; argnum++)
+    {
+      int len;
+      struct type *arg_type;
+
+      arg_type = check_typedef (VALUE_TYPE (args[argnum]));
+      len = TYPE_LENGTH (arg_type);
+
+      /* ANSI C code passes float arguments as integers, K&R code
+         passes float arguments as doubles.  Correct for this here.  */
+      if (TYPE_CODE_FLT == TYPE_CODE (arg_type) && REGISTER_SIZE == len)
+	nstack_size += FP_REGISTER_VIRTUAL_SIZE;
+      else
+	nstack_size += len;
+    }
+
+  /* Allocate room on the stack, and initialize our stack frame
+     pointer.  */
+  fp = NULL;
+  if (nstack_size > 0)
+    {
+      sp -= nstack_size;
+      fp = (char *) sp;
+    }
+
+  /* Initialize the integer argument register pointer.  */
+  argreg = A1_REGNUM;
+
+  /* The struct_return pointer occupies the first parameter passing
+     register.  */
+  if (struct_return)
+    write_register (argreg++, struct_addr);
+
+  /* Process arguments from left to right.  Store as many as allowed
+     in the parameter passing registers (A1-A4), and save the rest on
+     the temporary stack.  */
+  for (argnum = 0; argnum < nargs; argnum++)
+    {
+      int len;
+      char *val;
+      double dbl_arg;
+      CORE_ADDR regval;
+      enum type_code typecode;
+      struct type *arg_type, *target_type;
+
+      arg_type = check_typedef (VALUE_TYPE (args[argnum]));
+      target_type = TYPE_TARGET_TYPE (arg_type);
+      len = TYPE_LENGTH (arg_type);
+      typecode = TYPE_CODE (arg_type);
+      val = (char *) VALUE_CONTENTS (args[argnum]);
+
+      /* ANSI C code passes float arguments as integers, K&R code
+         passes float arguments as doubles.  The .stabs record for 
+         for ANSI prototype floating point arguments records the
+         type as FP_INTEGER, while a K&R style (no prototype)
+         .stabs records the type as FP_FLOAT.  In this latter case
+         the compiler converts the float arguments to double before
+         calling the function.  */
+      if (TYPE_CODE_FLT == typecode && REGISTER_SIZE == len)
+	{
+	  /* Float argument in buffer is in host format.  Read it and 
+	     convert to DOUBLEST, and store it in target double.  */
+	  DOUBLEST dblval;
+	  
+	  len = TARGET_DOUBLE_BIT / TARGET_CHAR_BIT;
+	  floatformat_to_doublest (HOST_FLOAT_FORMAT, val, &dblval);
+	  store_floating (&dbl_arg, len, dblval);
+	  val = (char *) &dbl_arg;
+	}
+
+      /* If the argument is a pointer to a function, and it is a Thumb
+         function, set the low bit of the pointer.  */
+      if (TYPE_CODE_PTR == typecode
+	  && NULL != target_type
+	  && TYPE_CODE_FUNC == TYPE_CODE (target_type))
+	{
+	  CORE_ADDR regval = extract_address (val, len);
+	  if (arm_pc_is_thumb (regval))
+	    store_address (val, len, MAKE_THUMB_ADDR (regval));
+	}
+
+      /* Copy the argument to general registers or the stack in
+         register-sized pieces.  Large arguments are split between
+         registers and stack.  */
+      while (len > 0)
+	{
+	  int partial_len = len < REGISTER_SIZE ? len : REGISTER_SIZE;
+
+	  if (argreg <= ARM_LAST_ARG_REGNUM)
+	    {
+	      /* It's an argument being passed in a general register.  */
+	      regval = extract_address (val, partial_len);
+	      write_register (argreg++, regval);
+	    }
+	  else
+	    {
+	      /* Push the arguments onto the stack.  */
+	      write_memory ((CORE_ADDR) fp, val, REGISTER_SIZE);
+	      fp += REGISTER_SIZE;
+	    }
+
+	  len -= partial_len;
+	  val += partial_len;
+	}
+    }
+
+  /* Return adjusted stack pointer.  */
+  return sp;
+}
+
 void
 _initialize_arm_linux_tdep (void)
 {