It is needed to restore PSR just before return because condition
codes are dirty after the CMP instructions and this may cause
undefined program behavior after returning from the switching
procedure (on following branch instruction, for example).
---
cpukit/score/cpu/sparc/syscall.S | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/cpukit/score/cpu/sparc/syscall.S b/cpukit/score/cpu/sparc/syscall.S
index 603ed7a738..bfd070a214 100644
--- a/cpukit/score/cpu/sparc/syscall.S
+++ b/cpukit/score/cpu/sparc/syscall.S
@@ -241,12 +241,16 @@ SYM(syscall_lazy_fp_switch):
.Lfp_restore_done:
+ mov %l0, %psr ! Resore condition codes. PSR[EF] is 1 here
+ nop; nop ! PSR write delay
+
/* Now, retry the floating point instruction with PSR[EF] == 1 */
jmp %l1
rett %l2
.Lillegal_use_of_floating_point_unit:
+ mov %l0, %psr ! Restore condition codes. Write delay 3 instr
sethi %hi(_Internal_error), %l1
or %l1, %lo(_Internal_error), %l1
mov 38, %i0
--
2.17.1
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