Implement support for big-endian hosts

Signed-off-by: Chih-Min Chao <chihmin.chao@sifive.com>

1 files changed, 22 insertions, 14 deletions

diff --git a/riscv/decode.h b/riscv/decode.h
index 2fb8192..3e759a3 100644
--- a/riscv/decode.h
+++ b/riscv/decode.h
@@ -7,10 +7,6 @@
 # error spike requires a two''s-complement c++ implementation
 #endif
 
-#ifdef WORDS_BIGENDIAN
-# error spike requires a little-endian host
-#endif
-
 #include <algorithm>
 #include <cstdint>
 #include <string.h>
@@ -69,6 +65,23 @@ const int NCSR = 4096;
 #define MAX_INSN_LENGTH 8
 #define PC_ALIGN 2
 
+#ifdef WORDS_BIGENDIAN
+  // Elements are stored in opposite order, see comment in processor.h
+  #define TAIL_ZERO(x) \
+    uint8_t *tail = &P.VU.elt<uint8_t>(rd_num, vl * (x) - 1); \
+    memset(tail - (P.VU.vlmax - vl) * (x), 0, (P.VU.vlmax - vl) * (x));
+  #define TAIL_ZERO_REDUCTION(x) \
+    uint8_t *tail = (uint8_t *)&P.VU.elt<type_sew_t<x>::type>(rd_num, 0); \
+    memset(tail - ((P.VU.get_vlen() - x) >> 3), 0, (P.VU.get_vlen() - x) >> 3);
+#else
+  #define TAIL_ZERO(x) \
+    uint8_t *tail = &P.VU.elt<uint8_t>(rd_num, vl * (x)); \
+    memset(tail, 0, (P.VU.vlmax - vl) * (x));
+  #define TAIL_ZERO_REDUCTION(x) \
+    uint8_t *tail = (uint8_t *)&P.VU.elt<type_sew_t<x>::type>(rd_num, 1); \
+    memset(tail, 0, (P.VU.get_vlen() - x) >> 3);
+#endif
+
 typedef uint64_t insn_bits_t;
 class insn_t
 {
@@ -486,8 +499,7 @@ static inline bool is_overlaped(const int astart, const int asize,
 
 #define VI_TAIL_ZERO(elm) \
   if (vl != 0 && vl < P.VU.vlmax && P.VU.TZ) { \
-    uint8_t *tail = &P.VU.elt<uint8_t>(rd_num, vl * ((sew >> 3) * elm)); \
-    memset(tail, 0, (P.VU.vlmax - vl) * ((sew >> 3) * elm)); \
+    TAIL_ZERO((sew >> 3) * elm); \
   }
 
 #define VI_TAIL_ZERO_MASK(dst) \
@@ -518,8 +530,7 @@ static inline bool is_overlaped(const int astart, const int asize,
 #define VI_LOOP_WIDEN_END \
   } \
   if (vl != 0 && vl < P.VU.vlmax && P.VU.TZ){ \
-    uint8_t *tail = &P.VU.elt<uint8_t>(rd_num, vl * ((sew >> 3) * 2)); \
-    memset(tail, 0, (P.VU.vlmax - vl) * ((sew >> 3) * 2)); \
+    TAIL_ZERO((sew >> 3) * 2); \
   }\
   P.VU.vstart = 0;
 
@@ -528,8 +539,7 @@ static inline bool is_overlaped(const int astart, const int asize,
   if (vl > 0) { \
     vd_0_des = vd_0_res; \
     if (P.VU.TZ) { \
-        uint8_t *tail = (uint8_t *)&P.VU.elt<type_sew_t<x>::type>(rd_num, 1); \
-        memset(tail, 0, (P.VU.get_vlen() - x) >> 3); \
+      TAIL_ZERO_REDUCTION(x); \
     } \
   } \
   P.VU.vstart = 0; 
@@ -1638,16 +1648,14 @@ for (reg_t i = 0; i < vlmax && P.VU.vl != 0; ++i) { \
 #define VI_VFP_LOOP_END \
   } \
   if (vl != 0 && vl < P.VU.vlmax && P.VU.TZ){ \
-    uint8_t *tail = &P.VU.elt<uint8_t>(rd_num, vl * ((P.VU.vsew >> 3) * 1)); \
-    memset(tail, 0, (P.VU.vlmax - vl) * ((P.VU.vsew >> 3) * 1)); \
+    TAIL_ZERO((P.VU.vsew >> 3) * 1); \
   }\
   P.VU.vstart = 0; \
 
 #define VI_VFP_LOOP_WIDE_END \
   } \
   if (vl != 0 && vl < P.VU.vlmax && P.VU.TZ){ \
-    uint8_t *tail = &P.VU.elt<uint8_t>(rd_num, vl * ((P.VU.vsew >> 3) * 2)); \
-    memset(tail, 0, (P.VU.vlmax - vl) * ((P.VU.vsew >> 3) * 2)); \
+    TAIL_ZERO((P.VU.vsew >> 3) * 2); \
   }\
   P.VU.vstart = 0; \
   set_fp_exceptions;