target-arm: A64: provide functions for accessing FPCR and FPSR

The information which AArch32 holds in the FPSCR is split for
AArch64 into two logically distinct registers, FPSR and FPCR.
Since they are carefully arranged to use non-overlapping bits,
we leave the underlying state in the same place, and provide
accessor functions which just update the appropriate bits
via vfp_get_fpscr() and vfp_set_fpscr().
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NRichard Henderson <rth@twiddle.net>

target-arm/cpu.h

@@ -447,6 +447,34 @@ static inline void xpsr_write(CPUARMState *env, uint32_t val, uint32_t mask)
 uint32_t vfp_get_fpscr(CPUARMState *env);
 void vfp_set_fpscr(CPUARMState *env, uint32_t val);
 
+/* For A64 the FPSCR is split into two logically distinct registers,
+ * FPCR and FPSR. However since they still use non-overlapping bits
+ * we store the underlying state in fpscr and just mask on read/write.
+ */
+#define FPSR_MASK 0xf800009f
+#define FPCR_MASK 0x07f79f00
+static inline uint32_t vfp_get_fpsr(CPUARMState *env)
+{
+    return vfp_get_fpscr(env) & FPSR_MASK;
+}
+
+static inline void vfp_set_fpsr(CPUARMState *env, uint32_t val)
+{
+    uint32_t new_fpscr = (vfp_get_fpscr(env) & ~FPSR_MASK) | (val & FPSR_MASK);
+    vfp_set_fpscr(env, new_fpscr);
+}
+
+static inline uint32_t vfp_get_fpcr(CPUARMState *env)
+{
+    return vfp_get_fpscr(env) & FPCR_MASK;
+}
+
+static inline void vfp_set_fpcr(CPUARMState *env, uint32_t val)
+{
+    uint32_t new_fpscr = (vfp_get_fpscr(env) & ~FPCR_MASK) | (val & FPCR_MASK);
+    vfp_set_fpscr(env, new_fpscr);
+}
+
 enum arm_cpu_mode {
   ARM_CPU_MODE_USR = 0x10,
   ARM_CPU_MODE_FIQ = 0x11,