When creating a new thread, inherit floating-point environment from

current thread, this is required by POSIX pthread_create document.

1 files changed, 30 insertions, 0 deletions

diff --git a/sys/i386/isa/npx.c b/sys/i386/isa/npx.c
index bc39629..7b7f3a5 100644
--- a/sys/i386/isa/npx.c
+++ b/sys/i386/isa/npx.c
@@ -942,6 +942,36 @@ npxsetregs(td, addr)
 	curthread->td_pcb->pcb_flags |= PCB_NPXINITDONE;
 }
 
+/*
+ * POSIX requires new thread to inherit floating-point environment.
+ */
+void
+npx_fork_thread(struct thread *td, struct thread *newtd)
+{
+	union savefpu	*state;
+	u_int32_t	mxcsr;
+	u_int32_t	cw;
+
+	state = &newtd->td_pcb->pcb_save;
+	/* get control word */
+	if (npxgetregs(td, &newtd->td_pcb->pcb_save))
+		return;
+	if (cpu_fxsr) {
+		mxcsr = state->sv_xmm.sv_env.en_mxcsr;
+		cw = state->sv_xmm.sv_env.en_cw;
+	} else {
+		cw = state->sv_87.sv_env.en_cw;
+		mxcsr = 0;
+	}
+	bcopy(&npx_cleanstate, state, sizeof(*state));
+	if (cpu_fxsr) {
+		state->sv_xmm.sv_env.en_cw = cw;
+		state->sv_xmm.sv_env.en_mxcsr = mxcsr;
+	} else
+		state->sv_87.sv_env.en_cw = cw;
+	newtd->td_pcb->pcb_flags |= PCB_NPXINITDONE;
+}
+
 static void
 fpusave(addr)
 	union savefpu *addr;