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Re: [rfa/arm] Make arm float->double arg pass portable(ish)
- To: Andrew Cagney <ac131313 at cygnus dot com>
- Subject: Re: [rfa/arm] Make arm float->double arg pass portable(ish)
- From: Andrew Cagney <ac131313 at cygnus dot com>
- Date: Fri, 20 Jul 2001 17:33:58 -0400
- Cc: gdb-patches at sources dot redhat dot com
- References: <3B3CA824.5080308@cygnus.com>
> And the patch is really attached ....
Hmm, ScottB got back with some feed back and I'm, for the moment going
to withdraw this patch.
While I don't think there is anything techically wrong with my change,
it fixes the local code but reveals a deeper problem.
Check the functions arm-tdep.c:convert_{to,from}_extended() where it
converts a target byte ordered buffer into a host double using a cast.
Taking a step back, I think there is a more fundamental problem, that
conversion shouldn't even be necessary. I think the type of the cooked
register should be ``builtin_type_floatformat_arm_ext'' instead of being
cast into ``builtin_type_double''. At present we're part way there,
MIPS returns builtin_type_uint{32,64} depending on the architecture.
Andrew
PS: Remember, the *REGISTER_CONVERT* functions are this -><- far from
being marked as deprecated)
>
> OK?
>
> Andrew
>
> Hello,
>
> per discussion in the thread:
>
> http://sources.redhat.com/ml/gdb-patches/2001-06/msg00504.html
>
> this just addresses the ARM. It uses extract_floating() and store_floating() as the conversion functions. Those go out of their way to preserve accuracy.
>
> You'll notice that in the patch I deleted a comment. The coment was simply wrong. GDB keeps everything in target byte order.
>
> OK?
>
> Now to sort out findvar.c and that HOST_FLOAT_FORMAT stuff :-/
>
> Andrew
>
>
>
>
> 2001-06-29 Andrew Cagney <ac131313@redhat.com>
>
> * arm-tdep.c (arm_push_arguments): Use extract_floating and
> store_floating to perform floating point conversions.
> * arm-linux-tdep.c (arm_linux_push_arguments): Ditto.
>
> Index: arm-linux-tdep.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/arm-linux-tdep.c,v
> retrieving revision 1.8
> diff -p -r1.8 arm-linux-tdep.c
> *** arm-linux-tdep.c 2001/03/01 01:39:20 1.8
> --- arm-linux-tdep.c 2001/07/04 19:40:47
> *************** arm_linux_push_arguments (int nargs, val
> *** 159,165 ****
> {
> int len;
> char *val;
> - double dbl_arg;
> CORE_ADDR regval;
> enum type_code typecode;
> struct type *arg_type, *target_type;
> --- 159,164 ----
> *************** arm_linux_push_arguments (int nargs, val
> *** 179,192 ****
> 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
> --- 178,188 ----
> calling the function. */
> if (TYPE_CODE_FLT == typecode && REGISTER_SIZE == len)
> {
> DOUBLEST dblval;
> ! dblval = extract_floating (val, len);
> len = TARGET_DOUBLE_BIT / TARGET_CHAR_BIT;
> ! val = alloca (len);
> ! store_floating (val, len, dblval);
> }
>
> /* If the argument is a pointer to a function, and it is a Thumb
> Index: arm-tdep.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/arm-tdep.c,v
> retrieving revision 1.12
> diff -p -r1.12 arm-tdep.c
> *** arm-tdep.c 2001/03/06 08:21:05 1.12
> --- arm-tdep.c 2001/07/04 19:40:56
> *************** struct frame_extra_info
> *** 117,140 ****
> #define MAKE_THUMB_ADDR(addr) ((addr) | 1)
> #define UNMAKE_THUMB_ADDR(addr) ((addr) & ~1)
>
> - #define SWAP_TARGET_AND_HOST(buffer,len) \
> - do \
> - { \
> - if (TARGET_BYTE_ORDER != HOST_BYTE_ORDER) \
> - { \
> - char tmp; \
> - char *p = (char *)(buffer); \
> - char *q = ((char *)(buffer)) + len - 1; \
> - for (; p < q; p++, q--) \
> - { \
> - tmp = *q; \
> - *q = *p; \
> - *p = tmp; \
> - } \
> - } \
> - } \
> - while (0)
> -
> /* Will a function return an aggregate type in memory or in a
> register? Return 0 if an aggregate type can be returned in a
> register, 1 if it must be returned in memory. */
> --- 117,122 ----
> *************** arm_push_arguments (int nargs, value_ptr
> *** 1309,1315 ****
> {
> int len;
> char *val;
> - double dbl_arg;
> CORE_ADDR regval;
> enum type_code typecode;
> struct type *arg_type, *target_type;
> --- 1291,1296 ----
> *************** arm_push_arguments (int nargs, value_ptr
> *** 1329,1350 ****
> calling the function. */
> if (TYPE_CODE_FLT == typecode && REGISTER_SIZE == len)
> {
> ! float f;
> ! double d;
> ! char * bufo = (char *) &d;
> ! char * bufd = (char *) &dbl_arg;
> !
> ! len = sizeof (double);
> ! f = *(float *) val;
> ! SWAP_TARGET_AND_HOST (&f, sizeof (float)); /* adjust endianess */
> ! d = f;
> ! /* We must revert the longwords so they get loaded into the
> ! the right registers. */
> ! memcpy (bufd, bufo + len / 2, len / 2);
> ! SWAP_TARGET_AND_HOST (bufd, len / 2); /* adjust endianess */
> ! memcpy (bufd + len / 2, bufo, len / 2);
> ! SWAP_TARGET_AND_HOST (bufd + len / 2, len / 2); /* adjust endianess */
> ! val = (char *) &dbl_arg;
> }
> #if 1
> /* I don't know why this code was disable. The only logical use
> --- 1310,1320 ----
> calling the function. */
> if (TYPE_CODE_FLT == typecode && REGISTER_SIZE == len)
> {
> ! DOUBLEST dblval;
> ! dblval = extract_floating (val, len);
> ! len = TARGET_DOUBLE_BIT / TARGET_CHAR_BIT;
> ! val = alloca (len);
> ! store_floating (val, len, dblval);
> }
> #if 1
> /* I don't know why this code was disable. The only logical use
>