abrossard@watcgl.waterloo.edu (Alain Brossard) (10/11/88)
I'm porting gdb to a system using a 68020 with a floating point
chip (68881) on board. Going through the file m-sun3.h which has the
same hardware characteristics I think I've spotted a few incorrect
assumptions regarding the 68020 and the 68881:
The status register (SP_REGNUM) is only 2 bytes long and pushed on
the stack that way by the 68020 when it encounters an exception
(or interrupt).
REGISTER_NAMES:
"fpcontrol", "fpstatus", "fpiaddr", "fpcode", "fpflags" }
The 68881 has 3 control registers and not 5, am I to assume that
two of those are specific to the Sun?
/* Number of bytes of storage in the actual machine representation
for register N. On the 68000, all regs are 4 bytes
except the floating point regs which are 12 bytes. */
#define REGISTER_RAW_SIZE(N) (((unsigned)(N) - FP0_REGNUM) < 8 ? 12 : 4)
Again this is incorrect for the status register and for all normal
68020 registers if I read this correctly: all registers lower than FP8
are assumed to be size 12, which is obviously incorrect. Here is my
corrected version:
#define REGISTER_RAW_SIZE(N) \
(unsigned(N) == PS_REGNUM ? 2 : ((unsigned)(N) < FP0_REGNUM) ? 4 : \
((unsigned)(N) < FPC_REGNUM ? 12 : 4)
Same thing about the following two:
#define REGISTER_BYTE(N) \
((N) >= FPC_REGNUM ? (((N) - FPC_REGNUM) * 4) + 166 \
: (N) >= FP0_REGNUM ? (((N) - FP0_REGNUM) * 12) + 70 \
: ( (N) <= PS_REGNUM ? (N) * 4 : (N) * 4 - 2))
#define REGISTER_VIRTUAL_SIZE(N) \
(unsigned(N) == PS_REGNUM ? 2 : ((unsigned)(N) < FP0_REGNUM) ? 4 : \
((unsigned)(N) < FPC_REGNUM ? 8 : 4)
Also wrong is:
#define REGISTER_CONVERTIBLE(N) (((unsigned)(N) - FP0_REGNUM) < 8)
Since the non floating point registers don't need to be converted.
#define REGISTER_VIRTUAL_TYPE(N) \
(((unsigned)(N) - FP0_REGNUM) < 8 ? builtin_type_double : builtin_type_int)
(same incorrect test)
Alain Brossard
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
Alain Brossard, CS Dept., U. Waterloo, Waterloo, Ontario, Canada N2L 3G1
INTERNET:abrossard@watcgl.uwaterloo.ca
INTERNET:abrossard@watcgl.waterloo.edu
UUCP :uunet!watmath!watcgl!abrossard
EAN :abrossard@cgl.waterloo.cdnabrossard@watcgl.waterloo.edu (Alain Brossard) (10/11/88)
I forgot to specify the version: cgl$ more version.c /* Define the current version number of GDB. */ char *version = "2.7"; Alain Brossard