[PATCH v4 3/4] target/riscv: support vector extension csr

[LIU Zhiwei <zhiwei_liu@c-sky.com>]

The v0.7.1 specification does not define vector status within mstatus.
A future revision will define the privileged portion of the vector status.

Signed-off-by: LIU Zhiwei <zhiwei_liu@c-sky.com>
---
 target/riscv/cpu_bits.h | 15 +++++++++
 target/riscv/csr.c      | 72 +++++++++++++++++++++++++++++++++++++++--
 2 files changed, 84 insertions(+), 3 deletions(-)

diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
index e99834856c..1f588ebc14 100644
--- a/target/riscv/cpu_bits.h
+++ b/target/riscv/cpu_bits.h
@@ -29,6 +29,14 @@
 #define FSR_NXA             (FPEXC_NX << FSR_AEXC_SHIFT)
 #define FSR_AEXC            (FSR_NVA | FSR_OFA | FSR_UFA | FSR_DZA | FSR_NXA)
 
+/* Vector Fixed-Point round model */
+#define FSR_VXRM_SHIFT      9
+#define FSR_VXRM            (0x3 << FSR_VXRM_SHIFT)
+
+/* Vector Fixed-Point saturation flag */
+#define FSR_VXSAT_SHIFT     8
+#define FSR_VXSAT           (0x1 << FSR_VXSAT_SHIFT)
+
 /* Control and Status Registers */
 
 /* User Trap Setup */
@@ -48,6 +56,13 @@
 #define CSR_FRM             0x002
 #define CSR_FCSR            0x003
 
+/* User Vector CSRs */
+#define CSR_VSTART          0x008
+#define CSR_VXSAT           0x009
+#define CSR_VXRM            0x00a
+#define CSR_VL              0xc20
+#define CSR_VTYPE           0xc21
+
 /* User Timers and Counters */
 #define CSR_CYCLE           0xc00
 #define CSR_TIME            0xc01
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 0e34c292c5..4696c8c180 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -46,6 +46,10 @@ void riscv_set_csr_ops(int csrno, riscv_csr_operations *ops)
 static int fs(CPURISCVState *env, int csrno)
 {
 #if !defined(CONFIG_USER_ONLY)
+    /* loose check condition for fcsr in vector extension */
+    if ((csrno == CSR_FCSR) && (env->misa & RVV)) {
+        return 0;
+    }
     if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
         return -1;
     }
@@ -53,6 +57,11 @@ static int fs(CPURISCVState *env, int csrno)
     return 0;
 }
 
+static int vs(CPURISCVState *env, int csrno)
+{
+    return 0;
+}
+
 static int ctr(CPURISCVState *env, int csrno)
 {
 #if !defined(CONFIG_USER_ONLY)
@@ -158,8 +167,10 @@ static int read_fcsr(CPURISCVState *env, int csrno, target_ulong *val)
         return -1;
     }
 #endif
-    *val = (riscv_cpu_get_fflags(env) << FSR_AEXC_SHIFT)
-        | (env->frm << FSR_RD_SHIFT);
+    *val = (env->vext.vxrm << FSR_VXRM_SHIFT)
+            | (env->vext.vxsat << FSR_VXSAT_SHIFT)
+            | (riscv_cpu_get_fflags(env) << FSR_AEXC_SHIFT)
+            | (env->frm << FSR_RD_SHIFT);
     return 0;
 }
 
@@ -172,10 +183,60 @@ static int write_fcsr(CPURISCVState *env, int csrno, target_ulong val)
     env->mstatus |= MSTATUS_FS;
 #endif
     env->frm = (val & FSR_RD) >> FSR_RD_SHIFT;
+    env->vext.vxrm = (val & FSR_VXRM) >> FSR_VXRM_SHIFT;
+    env->vext.vxsat = (val & FSR_VXSAT) >> FSR_VXSAT_SHIFT;
     riscv_cpu_set_fflags(env, (val & FSR_AEXC) >> FSR_AEXC_SHIFT);
     return 0;
 }
 
+static int read_vtype(CPURISCVState *env, int csrno, target_ulong *val)
+{
+    *val = env->vext.vtype;
+    return 0;
+}
+
+static int read_vl(CPURISCVState *env, int csrno, target_ulong *val)
+{
+    *val = env->vext.vl;
+    return 0;
+}
+
+static int read_vxrm(CPURISCVState *env, int csrno, target_ulong *val)
+{
+    *val = env->vext.vxrm;
+    return 0;
+}
+
+static int read_vxsat(CPURISCVState *env, int csrno, target_ulong *val)
+{
+    *val = env->vext.vxsat;
+    return 0;
+}
+
+static int read_vstart(CPURISCVState *env, int csrno, target_ulong *val)
+{
+    *val = env->vext.vstart;
+    return 0;
+}
+
+static int write_vxrm(CPURISCVState *env, int csrno, target_ulong val)
+{
+    env->vext.vxrm = val;
+    return 0;
+}
+
+static int write_vxsat(CPURISCVState *env, int csrno, target_ulong val)
+{
+    env->vext.vxsat = val;
+    return 0;
+}
+
+static int write_vstart(CPURISCVState *env, int csrno, target_ulong val)
+{
+    env->vext.vstart = val;
+    return 0;
+}
+
 /* User Timers and Counters */
 static int read_instret(CPURISCVState *env, int csrno, target_ulong *val)
 {
@@ -877,7 +938,12 @@ static riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     [CSR_FFLAGS] =              { fs,   read_fflags,      write_fflags      },
     [CSR_FRM] =                 { fs,   read_frm,         write_frm         },
     [CSR_FCSR] =                { fs,   read_fcsr,        write_fcsr        },
-
+    /* Vector CSRs */
+    [CSR_VSTART] =              { vs,   read_vstart,      write_vstart      },
+    [CSR_VXSAT] =               { vs,   read_vxsat,       write_vxsat       },
+    [CSR_VXRM] =                { vs,   read_vxrm,        write_vxrm        },
+    [CSR_VL] =                  { vs,   read_vl                             },
+    [CSR_VTYPE] =               { vs,   read_vtype                          },
     /* User Timers and Counters */
     [CSR_CYCLE] =               { ctr,  read_instret                        },
     [CSR_INSTRET] =             { ctr,  read_instret                        },
-- 
2.23.0