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RISC-V: NaN-box FP values smaller than an FP register.

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The hardware requires that values in FP registers be NaN-boxed, so we must
extend them with 1's instead of 0's as we do for integer values.

	gdb/
	* riscv-tdep.c (riscv_push_dummy_call) <in_reg>: Check for value in
	FP reg smaller than FP reg size, and fill with -1 instead of 0.
This commit is contained in:
Jim Wilson 2018-10-22 14:11:55 -07:00
parent 270b9329b7
commit 3399f1b303
2 changed files with 15 additions and 2 deletions
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3
gdb/ChangeLog
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@ -1,5 +1,8 @@
2018-10-22 Jim Wilson <jimw@sifive.com>
* riscv-tdep.c (riscv_push_dummy_call) <in_reg>: Check for value in
FP reg smaller than FP reg size, and fill with -1 instead of 0.
* riscv-tdep.c (riscv_fpreg_d_type, riscv_fpreg_q_type): New.
(riscv_register_type): Use them.
(riscv_print_one_register_info): Handle union of floats same as float.

14
gdb/riscv-tdep.c
View File

@ -2408,7 +2408,12 @@ riscv_push_dummy_call (struct gdbarch *gdbarch,
gdb_byte tmp [sizeof (ULONGEST)];
gdb_assert (info->argloc[0].c_length <= info->length);
memset (tmp, 0, sizeof (tmp));
/* FP values in FP registers must be NaN-boxed. */
if (riscv_is_fp_regno_p (info->argloc[0].loc_data.regno)
&& info->argloc[0].c_length < call_info.flen)
memset (tmp, -1, sizeof (tmp));
else
memset (tmp, 0, sizeof (tmp));
memcpy (tmp, info->contents, info->argloc[0].c_length);
regcache->cooked_write (info->argloc[0].loc_data.regno, tmp);
second_arg_length =
@ -2447,7 +2452,12 @@ riscv_push_dummy_call (struct gdbarch *gdbarch,
gdb_assert ((riscv_is_fp_regno_p (info->argloc[1].loc_data.regno)
&& second_arg_length <= call_info.flen)
|| second_arg_length <= call_info.xlen);
memset (tmp, 0, sizeof (tmp));
/* FP values in FP registers must be NaN-boxed. */
if (riscv_is_fp_regno_p (info->argloc[1].loc_data.regno)
&& second_arg_length < call_info.flen)
memset (tmp, -1, sizeof (tmp));
else
memset (tmp, 0, sizeof (tmp));
memcpy (tmp, second_arg_data, second_arg_length);
regcache->cooked_write (info->argloc[1].loc_data.regno, tmp);
}