[Qemu-devel] [PATCH v3 03/12] target-arm: A64: provide functions for accessing FPCR and FPSR

[Peter Maydell <peter.maydell@linaro.org>]

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: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
---
 target-arm/cpu.h |   28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/target-arm/cpu.h b/target-arm/cpu.h
index ff7aac5..4807354 100644
--- a/target-arm/cpu.h
+++ b/target-arm/cpu.h
@@ -445,6 +445,34 @@ 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,
-- 
1.7.9.5