testsuite/gdb.arch/riscv-info-fcsr.exp

# Copyright 2022-2023 Free Software Foundation, Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# Check the formatting of the fcsr, fflags, and frm registers in the
# output of the 'info registers' command.

if {![istarget "riscv*-*-*"]} {
    verbose "Skipping ${gdb_test_file_name}."
    return
}

if { [gdb_skip_float_test] } {
    untested "no floating point support"
    return
}

standard_testfile

if {[prepare_for_testing "failed to prepare" $testfile $srcfile debug]} {
    return -1
}

if {![runto_main]} {
   return 0
}

# Merge FFLAGS_VALUE and FRM_VALUE into a single hexadecimal value
# that can be written to the fcsr register.  The two arguments should
# be the value of each of the two fields within the fcsr register.
proc merge_fflags_and_frm { fflags_value frm_value } {
    set fcsr_value 0x[format %x [expr $fflags_value | ($frm_value << 5)]]
    return $fcsr_value
}

# Use 'info registers' to check the current values of the fflags, frm,
# and fcsr registers.  The value in fcsr should consist of the
# FFLAGS_VALUE and FRM_VALUE, and the frm field of the fcsr register
# should have the text FRM_STRING associated with it.
proc check_fcsr { fflags_value frm_value frm_string } {
    # Merge fflags and frm values into a single fcsr value.
    set fcsr_value [merge_fflags_and_frm $fflags_value $frm_value]

    # Build up all the patterns we will need for this test.
    set frm_str_re [string_to_regexp "$frm_string"]
    set frm_val_re [format %d ${frm_value}]

    set nv [format %d [expr ($fflags_value >> 4) & 0x1]]
    set dz [format %d [expr ($fflags_value >> 3) & 0x1]]
    set of [format %d [expr ($fflags_value >> 2) & 0x1]]
    set uf [format %d [expr ($fflags_value >> 1) & 0x1]]
    set nx [format %d [expr ($fflags_value >> 0) & 0x1]]

    set fflags_pattern "NV:${nv} DZ:${dz} OF:${of} UF:${uf} NX:${nx}"
    set frm_pattern "FRM:${frm_val_re} \\\[${frm_str_re}\\\]"
    set fcsr_pattern "${fflags_pattern} ${frm_pattern}"

    # Now use 'info registers' to check the register values.
    array set reg_counts {}
    gdb_test_multiple "info registers \$fflags \$frm \$fcsr" "" {
	-re "^info registers\[^\r\n\]+\r\n" {
	    exp_continue
	}

	-re "^(frm)\\s+${frm_value}\\s+${frm_pattern}\r\n" {
	    set reg_name $expect_out(1,string)
	    incr reg_counts($reg_name)
	    exp_continue
	}

	-re "^(fflags)\\s+${fflags_value}\\s+${fflags_pattern}\r\n" {
	    set reg_name $expect_out(1,string)
	    incr reg_counts($reg_name)
	    exp_continue
	}

	-re "^(fcsr)\\s+${fcsr_value}\\s+${fcsr_pattern}\r\n" {
	    set reg_name $expect_out(1,string)
	    incr reg_counts($reg_name)
	    exp_continue
	}

	-re "^$::gdb_prompt $" {
	    pass $gdb_test_name
	}
    }

    # Check that each register is seen only once.
    foreach reg {fflags frm fcsr} {
	gdb_assert { $reg_counts($reg) == 1 } \
	    "check we saw $reg just once"
    }
}

# Set the fcsr register based on FFLAGS_VALUE and FRM_VALUE, then
# check that the value is displayed correctly in the 'info registers'
# output.  FRM_STRING should appear in the 'info registers' output
# next to the frm field.
proc test_fcsr { fflags_value frm_value frm_string } {
    # Merge fflags and frm values into a single fcsr value.
    set fcsr_value [merge_fflags_and_frm $fflags_value $frm_value]

    with_test_prefix "fcsr=${fcsr_value}" {
	# Set the fcsr value directly.
	gdb_test_no_output "set \$fcsr = ${fcsr_value}"

	with_test_prefix "set through fcsr" {
	    check_fcsr $fflags_value $frm_value $frm_string
	}

	# Reset fcsr register back to zero.
	gdb_test_no_output "set \$fcsr = 0x0" \
	    "reset fcsr back to 0x0"
	gdb_test "p/x \$fcsr" " = 0x0"

	# Now set fcsr value through fflags and frm.
	gdb_test_no_output "set \$fflags = ${fflags_value}"
	gdb_test_no_output "set \$frm = ${frm_value}"

	with_test_prefix "set through fflags and frm" {
	    check_fcsr $fflags_value $frm_value $frm_string
	}
    }
}

# Check each valid value of the fflags register.
for { set i 0 } { $i < 32 } { incr i } {
    test_fcsr 0x[format %x $i] 0x0 "RNE (round to nearest; ties to even)"
}

# Check each valid value of the frm register.
test_fcsr 0x0 0x1 "RTZ (Round towards zero)"
test_fcsr 0x0 0x2 "RDN (Round down towards -INF)"
test_fcsr 0x0 0x3 "RUP (Round up towards +INF)"
test_fcsr 0x0 0x4 "RMM (Round to nearest; ties to max magnitude)"
test_fcsr 0x0 0x5 "INVALID\[5\]"
test_fcsr 0x0 0x6 "INVALID\[6\]"
test_fcsr 0x0 0x7 "INVALID\[7\] (Dynamic rounding mode)"