x86_64 FPU: Set 64-bit precision for fadd/fsub/fsqrt etc.

On AMD64, GCC and the ABI expects the x87 unit to be running in 80/64 mode rather than 64/53 mode seen on i386. This corrects errors seen in long double tests involving runtime calculations. Previously, the results of these runtime calculations would get rounded due to use of 53-bit mantissas.
DragonFlyBSD · Jul 14, 2012 · 4e1f876 · 4e1f876
1 parent b4ff333
commit 4e1f876
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Showing 5 changed files with 6 additions and 6 deletions.
diff --git a/sys/platform/pc64/x86_64/machdep.c b/sys/platform/pc64/x86_64/machdep.c
@@ -1113,7 +1113,7 @@ exec_setregs(u_long entry, u_long stack, u_long ps_strings)
 	wrmsr(MSR_KGSBASE, 0);
 
 	/* Initialize the npx (if any) for the current process. */
-	npxinit(__INITIAL_NPXCW__);
+	npxinit(__INITIAL_FPUCW__);
 	crit_exit();
 
 	pcb->pcb_ds = _udatasel;

diff --git a/sys/platform/pc64/x86_64/mp_machdep.c b/sys/platform/pc64/x86_64/mp_machdep.c
@@ -305,7 +305,7 @@ init_secondary(void)
 	initializecpu();
 
 	/* set up FPU state on the AP */
-	npxinit(__INITIAL_NPXCW__);
+	npxinit(__INITIAL_FPUCW__);
 
 	/* disable the APIC, just to be SURE */
 	lapic->svr &= ~APIC_SVR_ENABLE;

diff --git a/sys/platform/pc64/x86_64/npx.c b/sys/platform/pc64/x86_64/npx.c
@@ -331,7 +331,7 @@ npxdna(void)
 	crit_enter();
 	if ((td->td_flags & (TDF_USINGFP | TDF_KERNELFP)) == 0) {
 		td->td_flags |= TDF_USINGFP;
-		npxinit(__INITIAL_NPXCW__);
+		npxinit(__INITIAL_FPUCW__);
 		didinit = 1;
 	}
 

diff --git a/sys/platform/vkernel64/x86_64/cpu_regs.c b/sys/platform/vkernel64/x86_64/cpu_regs.c
@@ -832,7 +832,7 @@ exec_setregs(u_long entry, u_long stack, u_long ps_strings)
 	pcb->pcb_fsbase = 0;	/* Values loaded from PCB on switch */
 	pcb->pcb_gsbase = 0;
 	/* Initialize the npx (if any) for the current process. */
-	npxinit(__INITIAL_NPXCW__);
+	npxinit(__INITIAL_FPUCW__);
 	crit_exit();
 
 	/*

diff --git a/sys/platform/vkernel64/x86_64/npx.c b/sys/platform/vkernel64/x86_64/npx.c
@@ -113,7 +113,7 @@ SYSCTL_INT(_hw, OID_AUTO, instruction_sse, CTLFLAG_RD,
 int
 npx_attach(device_t dev)
 {
-	npxinit(__INITIAL_NPXCW__);
+	npxinit(__INITIAL_FPUCW__);
 	return (0);
 }
 #endif
@@ -357,7 +357,7 @@ npxdna(struct trapframe *frame)
 	 */
 	if ((curthread->td_flags & TDF_USINGFP) == 0) {
 		curthread->td_flags |= TDF_USINGFP;
-		npxinit(__INITIAL_NPXCW__);
+		npxinit(__INITIAL_FPUCW__);
 		didinit = 1;
 	}