tests/tcg: add float_convd test

This is a simple transliteration of the float_convs test but this time
working with doubles. I'm used it to test the handling of vector
registers in gdbstub but wasn't able to find a non-ugly way to
automate it.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220419091020.3008144-23-alex.bennee@linaro.org>

tests/tcg/multiarch/float_convd.c

@@ -0,0 +1,106 @@
+/*
+ * Floating Point Convert Doubles to Various
+ *
+ * Copyright (c) 2019 Linaro
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <float.h>
+#include <fenv.h>
+
+
+#include "float_helpers.h"
+
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+
+typedef struct {
+    int flag;
+    char *desc;
+} float_mapping;
+
+float_mapping round_flags[] = {
+    { FE_TONEAREST, "to nearest" },
+#ifdef FE_UPWARD
+    { FE_UPWARD, "upwards" },
+#endif
+#ifdef FE_DOWNWARD
+    { FE_DOWNWARD, "downwards" },
+#endif
+#ifdef FE_TOWARDZERO
+    { FE_TOWARDZERO, "to zero" }
+#endif
+};
+
+static void print_input(double input)
+{
+    char *in_fmt = fmt_f64(input);
+    printf("from double: %s\n", in_fmt);
+    free(in_fmt);
+}
+
+static void convert_double_to_single(double input)
+{
+    float output;
+    char *out_fmt, *flag_fmt;
+
+    feclearexcept(FE_ALL_EXCEPT);
+
+    output = input;
+
+    flag_fmt = fmt_flags();
+    out_fmt = fmt_f32(output);
+    printf("  to single: %s (%s)\n", out_fmt, flag_fmt);
+    free(out_fmt);
+    free(flag_fmt);
+}
+
+#define xstr(a) str(a)
+#define str(a) #a
+
+#define CONVERT_DOUBLE_TO_INT(TYPE, FMT)                            \
+    static void convert_double_to_ ## TYPE(double input)            \
+    {                                                               \
+        TYPE ## _t output;                                          \
+        char *flag_fmt;                                             \
+        const char to[] = "to " xstr(TYPE);                         \
+        feclearexcept(FE_ALL_EXCEPT);                               \
+        output = input;                                             \
+        flag_fmt = fmt_flags();                                     \
+        printf("%11s: %" FMT " (%s)\n", to, output, flag_fmt);      \
+        free(flag_fmt);                                             \
+    }
+
+CONVERT_DOUBLE_TO_INT( int32, PRId32)
+CONVERT_DOUBLE_TO_INT(uint32, PRId32)
+CONVERT_DOUBLE_TO_INT( int64, PRId64)
+CONVERT_DOUBLE_TO_INT(uint64, PRId64)
+
+int main(int argc, char *argv[argc])
+{
+    int i, j, nums;
+
+    nums = get_num_f64();
+
+    for (i = 0; i < ARRAY_SIZE(round_flags); ++i) {
+        if (fesetround(round_flags[i].flag) != 0) {
+            printf("### Rounding %s skipped\n", round_flags[i].desc);
+            continue;
+        }
+        printf("### Rounding %s\n", round_flags[i].desc);
+        for (j = 0; j < nums; j++) {
+            double input = get_f64(j);
+            print_input(input);
+            convert_double_to_single(input);
+            convert_double_to_int32(input);
+            convert_double_to_int64(input);
+            convert_double_to_uint32(input);
+            convert_double_to_uint64(input);
+        }
+    }
+
+    return 0;
+}