+# This works in Ring 0 only [read DJGPP+MS-DOS+privileged DPMI host],
+# but it's safe to call it on any [supported] 32-bit platform...
+# Just check for [non-]zero return value...
+&function_begin_B("OPENSSL_instrument_halt","EXTRN\t_OPENSSL_ia32cap_P:DWORD");
+ &picmeup("ecx","OPENSSL_ia32cap_P");
+ &bt (&DWP(0,"ecx"),4);
+ &jnc (&label("nohalt")); # no TSC
+
+ &data_word(0x9058900e); # push %cs; pop %eax
+ &and ("eax",3);
+ &jnz (&label("nohalt")); # not enough privileges
+
+ &pushf ();
+ &pop ("eax")
+ &bt ("eax",9);
+ &jnc (&label("nohalt")); # interrupts are disabled
+
+ &rdtsc ();
+ &push ("edx");
+ &push ("eax");
+ &halt ();
+ &rdtsc ();
+
+ &sub ("eax",&DWP(0,"esp"));
+ &sbb ("edx",&DWP(4,"esp"));
+ &add ("esp",8);
+ &ret ();
+
+&set_label("nohalt");
+ &xor ("eax","eax");
+ &xor ("edx","edx");
+ &ret ();
+&function_end_B("OPENSSL_instrument_halt");
+
+# Essentially there is only one use for this function. Under DJGPP:
+#
+# #include <go32.h>
+# ...
+# i=OPENSSL_far_spin(_dos_ds,0x46c);
+# ...
+# to obtain the number of spins till closest timer interrupt.
+
+&function_begin_B("OPENSSL_far_spin");
+ &pushf ();
+ &pop ("eax")
+ &bt ("eax",9);
+ &jnc (&label("nospin")); # interrupts are disabled
+
+ &mov ("eax",&DWP(4,"esp"));
+ &mov ("ecx",&DWP(8,"esp"));
+ &data_word (0x90d88e1e); # push %ds, mov %eax,%ds
+ &xor ("eax","eax");
+ &mov ("edx",&DWP(0,"ecx"));
+ &jmp (&label("spin"));
+
+ &align (16);
+&set_label("spin");
+ &inc ("eax");
+ &cmp ("edx",&DWP(0,"ecx"));
+ &je (&label("spin"));
+
+ &data_word (0x1f909090); # pop %ds
+ &ret ();
+
+&set_label("nospin");
+ &xor ("eax","eax");
+ &xor ("edx","edx");
+ &ret ();
+&function_end_B("OPENSSL_far_spin");
+
+&function_begin_B("OPENSSL_wipe_cpu","EXTRN\t_OPENSSL_ia32cap_P:DWORD");
+ &xor ("eax","eax");
+ &xor ("edx","edx");
+ &picmeup("ecx","OPENSSL_ia32cap_P");
+ &mov ("ecx",&DWP(0,"ecx"));
+ &bt (&DWP(0,"ecx"),1);
+ &jnc (&label("no_x87"));
+ if ($sse2) {
+ &bt (&DWP(0,"ecx"),26);
+ &jnc (&label("no_sse2"));
+ &pxor ("xmm0","xmm0");
+ &pxor ("xmm1","xmm1");
+ &pxor ("xmm2","xmm2");
+ &pxor ("xmm3","xmm3");
+ &pxor ("xmm4","xmm4");
+ &pxor ("xmm5","xmm5");
+ &pxor ("xmm6","xmm6");
+ &pxor ("xmm7","xmm7");
+ &set_label("no_sse2");
+ }
+ # just a bunch of fldz to zap the fp/mm bank followed by finit...
+ &data_word(0xeed9eed9,0xeed9eed9,0xeed9eed9,0xeed9eed9,0x90e3db9b);
+&set_label("no_x87");
+ &lea ("eax",&DWP(4,"esp"));
+ &ret ();
+&function_end_B("OPENSSL_wipe_cpu");
+
+&function_begin_B("OPENSSL_atomic_add");
+ &mov ("edx",&DWP(4,"esp")); # fetch the pointer, 1st arg
+ &mov ("ecx",&DWP(8,"esp")); # fetch the increment, 2nd arg
+ &push ("ebx");
+ &nop ();
+ &mov ("eax",&DWP(0,"edx"));
+&set_label("spin");
+ &lea ("ebx",&DWP(0,"eax","ecx"));
+ &nop ();
+ &data_word(0x1ab10ff0); # lock; cmpxchg %ebx,(%edx) # %eax is envolved and is always reloaded
+ &jne (&label("spin"));
+ &mov ("eax","ebx"); # OpenSSL expects the new value
+ &pop ("ebx");
+ &ret ();
+&function_end_B("OPENSSL_atomic_add");
+
+&initseg("OPENSSL_cpuid_setup");