From 25a3be459084c12b2cbb44fd1ca2a5d0754cd0a3 Mon Sep 17 00:00:00 2001
From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Fri, 26 Oct 2018 07:57:42 +0100
Subject: [PATCH] forgot to mask off data being written within element

---
 riscv/sv_insn_redirect.cc | 20 +++++++++++---------
 riscv/sv_reg.h            |  4 ++++
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/riscv/sv_insn_redirect.cc b/riscv/sv_insn_redirect.cc
index 6e38eaf..5eb4f07 100644
--- a/riscv/sv_insn_redirect.cc
+++ b/riscv/sv_insn_redirect.cc
@@ -100,20 +100,21 @@ void (sv_proc_t::WRITE_REG)(reg_spec_t const& spec, sv_reg_t const& value)
     int bitwidth = get_bitwidth(_insn->reg_elwidth(reg, true), xlen);
     unsigned int shift = 0;
     unsigned int offs = 0;
-    if (spec.offset) {
+    if (spec.offset != NULL) {
         unsigned int nbytes = xlen / bitwidth;
         offs = *spec.offset;
         shift = offs % nbytes;
         offs /= nbytes;
-        fprintf(stderr, "writereg spec %ld bitwidth %d offs %d shift %d\n",
-                        spec.reg, bitwidth, offs, shift);
         reg += offs;
+        fprintf(stderr, "writereg spec %ld %lx bitwidth %d offs %d shift %d\n",
+                        reg, wval, bitwidth, offs, shift);
     }
     if (xlen != bitwidth)
     {
         uint64_t data = _insn->p->get_state()->XPR[reg];
         uint64_t mask = ((1UL<<bitwidth)-1UL) << (shift*bitwidth);
-        wval = wval << (shift*bitwidth); // gets element within the reg-block
+        wval = (uint64_t)(wval << (shift*bitwidth)); // element within reg-block
+        wval &= mask;
         uint64_t ndata = data & (uint64_t)(~mask); // masks off the right bits
         wval |= ndata;
         fprintf(stderr, "writereg %ld bitwidth %d offs %d shift %d %lx " \
@@ -140,7 +141,7 @@ reg_t (sv_proc_t::READ_REG)(reg_spec_t const& spec)
     int bitwidth = get_bitwidth(_insn->reg_elwidth(reg, true), xlen);
     int shift = 0;
     int offs = 0;
-    if (spec.offset && spec.reg != 2) { // XXX HACK on spec.reg != 2
+    if (spec.offset != NULL && spec.reg != 2) { // XXX HACK on spec.reg != 2
         int nbytes = xlen / bitwidth;
         offs = *spec.offset;
         shift = offs % nbytes;
@@ -260,7 +261,7 @@ sv_sreg_t (sv_proc_t::sext32)(sv_reg_t const& v)
 {
     uint64_t x = v;
     x = ((sreg_t)(int32_t)(x));
-    return sv_sreg_t((int64_t)x);
+    return sv_sreg_t((int64_t)x, v.get_xlen(), v.get_elwidth());
 }
 
 //sv_sreg_t (sv_proc_t::sext32)(sv_sreg_t const& v)
@@ -345,8 +346,8 @@ sv_reg_t sv_proc_t::rv_add(sv_reg_t const & lhs, sv_reg_t const & rhs)
 {
     uint8_t bitwidth = _insn->src_bitwidth;
     if (bitwidth == xlen) {
-        //fprintf(stderr, "add result %lx %lx %lx\n",
-        //        (uint64_t)lhs, (uint64_t)rhs, (uint64_t)(lhs + rhs));
+        fprintf(stderr, "add result %lx %lx %lx\n",
+                (uint64_t)lhs, (uint64_t)rhs, (uint64_t)(lhs + rhs));
         return lhs + rhs;
     }
     uint64_t vlhs = 0;
@@ -368,7 +369,8 @@ sv_reg_t sv_proc_t::rv_add(sv_reg_t const & lhs, sv_reg_t const & rhs)
         result = zext_bwid(result, bitwidth);
     }
     uint8_t reswidth = maxelwidth(lhs.get_elwidth(), rhs.get_elwidth());
-    //fprintf(stderr, "add result %ld\n", result);
+    fprintf(stderr, "add result sext %d wid %d %lx\n", _insn->signextended,
+                                                        reswidth, result);
     return sv_reg_t(result, xlen, reswidth); // XXX TODO: bitwidth
 }
 
diff --git a/riscv/sv_reg.h b/riscv/sv_reg.h
index 5dfcb35..8bdc940 100644
--- a/riscv/sv_reg.h
+++ b/riscv/sv_reg.h
@@ -60,6 +60,10 @@ public:
     sv_sreg_t(int64_t _reg) : sv_regbase_t(), reg(_reg) {} // default elwidth
     sv_sreg_t(int64_t _reg, uint8_t _elwidth) : sv_regbase_t(_elwidth),
                                                 reg(_reg) {}
+    sv_sreg_t(uint64_t _reg, int xlen, uint8_t _elwidth) :
+                sv_regbase_t(xlen, _elwidth), reg(_reg)
+                                                {}
+
 
     int64_t reg;
 public:
-- 
2.30.2