rvv: use zvqmac to enable vector qmac

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

riscv/decode.h

@@ -520,6 +520,7 @@ static inline bool is_aligned(const unsigned val, const unsigned pos)
 
 #define VI_CHECK_QSS(is_vs1) \
   require_vector;\
+  p->supports_extension(EXT_ZVQMAC); \
   require(P.VU.vflmul <= 2); \
   require(P.VU.vsew * 4 <= P.VU.ELEN); \
   require_align(insn.rd(), P.VU.vflmul * 4); \

riscv/processor.cc

@@ -261,6 +261,8 @@ void processor_t::parse_isa_string(const char* str)
         extension_table[EXT_ZVAMO] = true;
       } else if (ext_str == "zvlsseg") {
         extension_table[EXT_ZVLSSEG] = true;
+      } else if (ext_str == "zvqmac") {
+        extension_table[EXT_ZVQMAC] = true;
       } else {
         sprintf(error_msg, "unsupported extension '%s'", ext_str.c_str());
         bad_isa_string(str, error_msg);
@@ -293,6 +295,9 @@ void processor_t::parse_isa_string(const char* str)
 
   if (supports_extension(EXT_ZVLSSEG) && !supports_extension('V'))
     bad_isa_string(str, "'Zvlsseg' extension requires 'V'");
+
+  if (supports_extension(EXT_ZVQMAC) && !supports_extension('V'))
+    bad_isa_string(str, "'Zvqmac' extension requires 'V'");
 }
 
 void state_t::reset(reg_t max_isa)