Unmask IEEE 754 floating-point exceptions on x86-64.

Should this instead be part of Scheme's dynamic environment, like the
floating-point rounding mode?

diff --git a/src/microcode/cmpauxmd/x86-64.m4 b/src/microcode/cmpauxmd/x86-64.m4
index 5524b9a118f3bc2b56cf63538383d7ef39de3e86..6d5a523c19b3de9ba39989789eba0d9a8cae17e9 100644 (file)
--- a/src/microcode/cmpauxmd/x86-64.m4
+++ b/src/microcode/cmpauxmd/x86-64.m4
@@ -356,6 +356,24 @@ define_double(flonum_one,1.0)
 DECLARE_CODE_SEGMENT()
 declare_alignment(2)
 
+define_c_label(x86_64_fpe_reset_traps)
+       OP(push,q)      REG(rbp)
+       OP(mov,q)       TW(REG(rsp),REG(rbp))
+       OP(sub,q)       TW(IMM(8),REG(rsp))
+       stmxcsr         IND(REG(rsp))
+       # Clear 7 (invalid operation mask)
+       #       8 (denormalized operand mask)
+       #       9 (zero-divide exception mask)
+       #       10 (overflow exception mask)
+       #       11 (underflow exception mask)
+       #       15 (flush-to-zero (if set, gives non-IEEE semantics))
+       OP(and,l)       TW(IMM(HEX(ffff707f)),IND(REG(rsp)))
+       # Set   12 (precision exception mask)
+       OP(or,l)        TW(IMM(HEX(1000)),IND(REG(rsp)))
+       ldmxcsr         IND(REG(rsp))
+       leave
+       ret
+
 # C_to_interface passes control from C into Scheme.  To C it is a
 # unary procedure; its one argument is passed in rdi.  It saves the
 # state of the C world (the C frame pointer and stack pointer) and

diff --git a/src/microcode/cmpintmd/x86-64.c b/src/microcode/cmpintmd/x86-64.c
index 404abd4021282103c3bb4ca6f1bea99d5265b7a0..86144a79a6269cc712cb6dea5e2d2bec7e619863 100644 (file)
--- a/src/microcode/cmpintmd/x86-64.c
+++ b/src/microcode/cmpintmd/x86-64.c
@@ -223,6 +223,8 @@ x86_64_reset_hook (void)
   int offset = (COMPILER_REGBLOCK_N_FIXED * (sizeof (SCHEME_OBJECT)));
   unsigned char * rsi_value = ((unsigned char *) Registers);
 
+  x86_64_fpe_reset_traps ();
+
   /* These must match machines/x86-64/lapgen.scm */
 
   SETUP_REGISTER (asm_scheme_to_interface);            /* 0 */

diff --git a/src/microcode/cmpintmd/x86-64.h b/src/microcode/cmpintmd/x86-64.h
index f296eab47c8765754cb0d7314377c175ae73ccd9..0a7548fcec38c660521c4e60b89e14f4a9b784f6 100644 (file)
--- a/src/microcode/cmpintmd/x86-64.h
+++ b/src/microcode/cmpintmd/x86-64.h
@@ -117,6 +117,7 @@ entry       0               MOV     AL,code         0xB0, code-byte
 */
 \f
 #define ASM_RESET_HOOK x86_64_reset_hook
+#define FPE_RESET_TRAPS x86_64_fpe_reset_traps
 
 #define CMPINT_USE_STRUCS 1
 
@@ -173,7 +174,7 @@ typedef byte_t insn_t;
 #  define ASM_ENTRY_POINT(name) name
 #endif
 
-extern int ASM_ENTRY_POINT (x86_64_interface_initialize) (void);
+extern void ASM_ENTRY_POINT (x86_64_fpe_reset_traps) (void);
 
 extern void asm_assignment_trap (void);
 extern void asm_dont_serialize_cache (void);