1 files changed, 37 insertions, 0 deletions
diff --git a/tests/test32.c b/tests/test32.c
new file mode 100644
index 00000000..ae123de9
--- /dev/null
+++ b/tests/test32.c
@@ -0,0 +1,37 @@
+// gcc -mfpmath=387 -o test32 test32.c -lm
+#include <stdio.h>
+#include <stdint.h>
+#include <math.h>
+
+volatile double test_values[] = {
+    3.0, 2.0, 0.1
+};
+
+#define TEST_X87(INSN_LOAD, INSN_OP, VAL_IDX)                  \
+    do {                                                       \
+        volatile double result;                                \
+        volatile double* val_ptr = &test_values[VAL_IDX];      \
+        __asm__ volatile(                                      \
+            "fldcw %[low]\n\t" INSN_LOAD "\n\t" INSN_OP "\n\t" \
+            "fstl %[res]\n\t"                                  \
+            "fldcw %[orig]\n\t"                                \
+            : [res] "=m"(result)                               \
+            : [low] "m"(low_cw),                               \
+            [orig] "m"(original_cw),                           \
+            [val] "m"(*val_ptr)                                \
+            : "st", "st(1)");                                  \
+        printf("%-16s: %016lx\n", #INSN_OP, *(uint64_t*)&result); \
+    } while (0)
+
+uint16_t original_cw, low_cw;
+
+int main()
+{
+    __asm__ volatile("fstcw %0" : "=m"(original_cw));
+    low_cw = original_cw & ~((uint16_t)0x0300);
+
+    TEST_X87("fld1; fldl %3", "fdivrp", 0);   // 1.0 / 3.0
+    TEST_X87("fldl %3", "fsqrt", 1);          // sqrt(2.0)
+    TEST_X87("fldl %3; fldl %3", "faddp", 2); // 0.1 + 0.1
+    return 0;
+}