[Valgrind-developers] [valgrind] s390x: Fix disassembly for various DFP and BFP opcodes (BZ 495817)

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commit 72de8eaf53d77b0aa51266864f5a339b787ca24c
Author: Florian Krohm <fl...@ei...>
Date:   Sun Mar 30 20:51:33 2025 +0000

    s390x: Fix disassembly for various DFP and BFP opcodes  (BZ 495817)
    
    Specifically:
    - DFP: add, subtract, divide, multiply
    - BFP: load FP integer, load rounded
    
    Change function names from e.g. s390_irgen/emit_LDXBR to
    s390_irgen/emit_LDXBRA because LDXBR does not have m3 and m4 operands.
    Adjust the returned mnemonic accordingly.
    
    New function s390_format_RRF_UUFF2 for FI[DEX]BRA.
    
    Add adtra_like_disasm to disassemble opcodes for DFP arithmetic.
    
    Part of fixing https://bugs.kde.org/show_bug.cgi?id=495817

Diff:
---
 VEX/priv/guest_s390_toIR.c |  59 +++++++++++++----------
 VEX/priv/host_s390_defs.c  | 116 ++++++++++++---------------------------------
 VEX/priv/s390_disasm.c     |  18 +++++++
 VEX/priv/s390_disasm.h     |   1 +
 4 files changed, 84 insertions(+), 110 deletions(-)

diff --git a/VEX/priv/guest_s390_toIR.c b/VEX/priv/guest_s390_toIR.c
index 7b029623d6..b870b77fe4 100644
--- a/VEX/priv/guest_s390_toIR.c
+++ b/VEX/priv/guest_s390_toIR.c
@@ -3094,7 +3094,18 @@ s390_format_RRF_UUFF(const HChar *(*irgen)(UChar m3, UChar m4, UChar r1,
    const HChar *mnm = irgen(m3, m4, r1, r2);
 
    if (UNLIKELY(vex_traceflags & VEX_TRACE_FE))
-      S390_DISASM(MNM(mnm), FPR(r1), UINT(m3), FPR(r2), UINT(m4));
+      S390_DISASM(XMNM(mnm, fp_convf_disasm), FPR(r1), MASK(m3), FPR(r2), MASK(m4));
+}
+
+static void
+s390_format_RRF_UUFF2(const HChar *(*irgen)(UChar m3, UChar m4, UChar r1,
+                                           UChar r2),
+                     UChar m3, UChar m4, UChar r1, UChar r2)
+{
+   const HChar *mnm = irgen(m3, m4, r1, r2);
+
+   if (UNLIKELY(vex_traceflags & VEX_TRACE_FE))
+      S390_DISASM(XMNM(mnm, fp_convt_disasm), FPR(r1), MASK(m3), FPR(r2), MASK(m4));
 }
 
 static void
@@ -3191,7 +3202,7 @@ s390_format_RRF_FUFF2(const HChar *(*irgen)(UChar, UChar, UChar, UChar),
    const HChar *mnm = irgen(r3, m4, r1, r2);
 
    if (UNLIKELY(vex_traceflags & VEX_TRACE_FE))
-      S390_DISASM(MNM(mnm), FPR(r1), FPR(r2), FPR(r3), UINT(m4));
+      S390_DISASM(XMNM(mnm, adtra_like_disasm), FPR(r1), FPR(r2), FPR(r3), MASK(m4));
 }
 
 static void
@@ -11807,8 +11818,8 @@ s390_irgen_LDEB(UChar r1, IRTemp op2addr)
 }
 
 static const HChar *
-s390_irgen_LEDBR(UChar m3, UChar m4 __attribute__((unused)),
-                 UChar r1, UChar r2)
+s390_irgen_LEDBRA(UChar m3, UChar m4 __attribute__((unused)),
+                  UChar r1, UChar r2)
 {
    if (! s390_host_has_fpext && m3 != S390_BFP_ROUND_PER_FPC) {
       emulation_warning(EmWarn_S390X_fpext_rounding);
@@ -11820,7 +11831,7 @@ s390_irgen_LEDBR(UChar m3, UChar m4 __attribute__((unused)),
    put_fpr_w0(r1, binop(Iop_F64toF32, mkexpr(encode_bfp_rounding_mode(m3)),
                         mkexpr(op)));
 
-   return "ledbr";
+   return "ledbra";
 }
 
 static const HChar *
@@ -11988,7 +11999,7 @@ s390_irgen_ADTRA(UChar r3, UChar m4, UChar r1, UChar r2)
       s390_cc_thunk_putF(S390_CC_OP_DFP_RESULT_64, result);
       put_dpr_dw0(r1, mkexpr(result));
    }
-   return (m4 == 0) ? "adtr" : "adtra";
+   return "adtra";
 }
 
 static const HChar *
@@ -14970,8 +14981,8 @@ s390_irgen_LPXBR(UChar r1, UChar r2)
 }
 
 static const HChar *
-s390_irgen_LDXBR(UChar m3, UChar m4 __attribute__((unused)),
-                 UChar r1, UChar r2)
+s390_irgen_LDXBRA(UChar m3, UChar m4 __attribute__((unused)),
+                  UChar r1, UChar r2)
 {
    if (! s390_host_has_fpext && m3 != S390_BFP_ROUND_PER_FPC) {
       emulation_warning(EmWarn_S390X_fpext_rounding);
@@ -14983,12 +14994,12 @@ s390_irgen_LDXBR(UChar m3, UChar m4 __attribute__((unused)),
                         get_fpr_pair(r2)));
    put_fpr_dw0(r1, mkexpr(result));
 
-   return "ldxbr";
+   return "ldxbra";
 }
 
 static const HChar *
-s390_irgen_LEXBR(UChar m3, UChar m4 __attribute__((unused)),
-                 UChar r1, UChar r2)
+s390_irgen_LEXBRA(UChar m3, UChar m4 __attribute__((unused)),
+                  UChar r1, UChar r2)
 {
    if (! s390_host_has_fpext && m3 != S390_BFP_ROUND_PER_FPC) {
       emulation_warning(EmWarn_S390X_fpext_rounding);
@@ -15000,7 +15011,7 @@ s390_irgen_LEXBR(UChar m3, UChar m4 __attribute__((unused)),
                         get_fpr_pair(r2)));
    put_fpr_w0(r1, mkexpr(result));
 
-   return "lexbr";
+   return "lexbra";
 }
 
 static const HChar *
@@ -20745,18 +20756,18 @@ s390_decode_4byte_and_irgen(const UChar *bytes)
                                    RRE_r2(ovl));  goto ok;
    case 0xb343: s390_format_RRE_FF(s390_irgen_LCXBR, RRE_r1(ovl),
                                    RRE_r2(ovl));  goto ok;
-   case 0xb344: s390_format_RRF_UUFF(s390_irgen_LEDBR, RRF2_m3(ovl),
-                                     RRF2_m4(ovl), RRF2_r1(ovl),
-                                     RRF2_r2(ovl));  goto ok;
-   case 0xb345: s390_format_RRF_UUFF(s390_irgen_LDXBR, RRF2_m3(ovl),
+   case 0xb344: s390_format_RRF_UUFF(s390_irgen_LEDBRA, RRF2_m3(ovl),
                                      RRF2_m4(ovl), RRF2_r1(ovl),
                                      RRF2_r2(ovl));  goto ok;
-   case 0xb346: s390_format_RRF_UUFF(s390_irgen_LEXBR, RRF2_m3(ovl),
+   case 0xb345: s390_format_RRF_UUFF(s390_irgen_LDXBRA, RRF2_m3(ovl),
                                      RRF2_m4(ovl), RRF2_r1(ovl),
                                      RRF2_r2(ovl));  goto ok;
-   case 0xb347: s390_format_RRF_UUFF(s390_irgen_FIXBRA, RRF2_m3(ovl),
+   case 0xb346: s390_format_RRF_UUFF(s390_irgen_LEXBRA, RRF2_m3(ovl),
                                      RRF2_m4(ovl), RRF2_r1(ovl),
                                      RRF2_r2(ovl));  goto ok;
+   case 0xb347: s390_format_RRF_UUFF2(s390_irgen_FIXBRA, RRF2_m3(ovl),
+                                      RRF2_m4(ovl), RRF2_r1(ovl),
+                                      RRF2_r2(ovl));  goto ok;
    case 0xb348: s390_format_RRE_FF(s390_irgen_KXBR, RRE_r1(ovl),
                                    RRE_r2(ovl));  goto ok;
    case 0xb349: s390_format_RRE_FF(s390_irgen_CXBR, RRE_r1(ovl),
@@ -20772,15 +20783,15 @@ s390_decode_4byte_and_irgen(const UChar *bytes)
    case 0xb350: /* TBEDR */ goto unimplemented;
    case 0xb351: /* TBDR */ goto unimplemented;
    case 0xb353: /* DIEBR */ goto unimplemented;
-   case 0xb357: s390_format_RRF_UUFF(s390_irgen_FIEBRA, RRF2_m3(ovl),
-                                     RRF2_m4(ovl), RRF2_r1(ovl),
-                                     RRF2_r2(ovl));  goto ok;
+   case 0xb357: s390_format_RRF_UUFF2(s390_irgen_FIEBRA, RRF2_m3(ovl),
+                                      RRF2_m4(ovl), RRF2_r1(ovl),
+                                      RRF2_r2(ovl));  goto ok;
    case 0xb358: /* THDER */ goto unimplemented;
    case 0xb359: /* THDR */ goto unimplemented;
    case 0xb35b: /* DIDBR */ goto unimplemented;
-   case 0xb35f: s390_format_RRF_UUFF(s390_irgen_FIDBRA, RRF2_m3(ovl),
-                                     RRF2_m4(ovl), RRF2_r1(ovl),
-                                     RRF2_r2(ovl));  goto ok;
+   case 0xb35f: s390_format_RRF_UUFF2(s390_irgen_FIDBRA, RRF2_m3(ovl),
+                                      RRF2_m4(ovl), RRF2_r1(ovl),
+                                      RRF2_r2(ovl));  goto ok;
    case 0xb360: /* LPXR */ goto unimplemented;
    case 0xb361: /* LNXR */ goto unimplemented;
    case 0xb362: /* LTXR */ goto unimplemented;
diff --git a/VEX/priv/host_s390_defs.c b/VEX/priv/host_s390_defs.c
index 684d173588..c503d6ddeb 100644
--- a/VEX/priv/host_s390_defs.c
+++ b/VEX/priv/host_s390_defs.c
@@ -4383,12 +4383,8 @@ s390_emit_LEDBRA(UChar *p, UChar m3, UChar m4, UChar r1, UChar r2)
    vassert(m4 == 0);
    vassert(m3 == 0 || s390_host_has_fpext);
 
-   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM)) {
-      if (m3 == 0)
-         S390_DISASM(MNM("ledbr"), FPR(r1), FPR(r2));
-      else
-         S390_DISASM(MNM("ledbra"), FPR(r1), UINT(m3), FPR(r2), UINT(m4));
-   }
+   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM))
+      S390_DISASM(XMNM("ledbra", fp_convf_disasm), FPR(r1), MASK(m3), FPR(r2), MASK(m4));
 
    return emit_RRF2(p, 0xb3440000, m3, m4, r1, r2);
 }
@@ -4400,12 +4396,8 @@ s390_emit_LDXBRA(UChar *p, UChar m3, UChar m4, UChar r1, UChar r2)
    vassert(m4 == 0);
    vassert(m3 == 0 || s390_host_has_fpext);
 
-   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM)) {
-      if (m3 == 0)
-         S390_DISASM(MNM("ldxbr"), FPR(r1), FPR(r2));
-      else
-         S390_DISASM(MNM("ldxbra"), FPR(r1), UINT(m3), FPR(r2), UINT(m4));
-   }
+   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM))
+      S390_DISASM(XMNM("ldxbra", fp_convf_disasm), FPR(r1), MASK(m3), FPR(r2), MASK(m4));
 
    return emit_RRF2(p, 0xb3450000, m3, m4, r1, r2);
 }
@@ -4417,12 +4409,8 @@ s390_emit_LEXBRA(UChar *p, UChar m3, UChar m4, UChar r1, UChar r2)
    vassert(m4 == 0);
    vassert(m3 == 0 || s390_host_has_fpext);
 
-   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM)) {
-      if (m3 == 0)
-         S390_DISASM(MNM("lexbr"), FPR(r1), FPR(r2));
-      else
-         S390_DISASM(MNM("lexbra"), FPR(r1), UINT(m3), FPR(r2), UINT(m4));
-   }
+   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM))
+      S390_DISASM(XMNM("lexbra", fp_convf_disasm), FPR(r1), MASK(m3), FPR(r2), MASK(m4));
 
    return emit_RRF2(p, 0xb3460000, m3, m4, r1, r2);
 }
@@ -4433,12 +4421,8 @@ s390_emit_FIEBRA(UChar *p, UChar m3, UChar m4, UChar r1, UChar r2)
 {
    vassert(m3 == 0 || s390_host_has_fpext);
 
-   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM)) {
-      if (m4 == 0)
-         S390_DISASM(MNM("fiebr"), FPR(r1), UINT(m3), FPR(r2));
-      else
-         S390_DISASM(MNM("fiebra"), FPR(r1), UINT(m3), FPR(r2), UINT(m4));
-   }
+   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM))
+      S390_DISASM(XMNM("fiebra", fp_convt_disasm), FPR(r1), MASK(m3), FPR(r2), MASK(m4));
 
    return emit_RRF2(p, 0xb3570000, m3, m4, r1, r2);
 }
@@ -4449,12 +4433,8 @@ s390_emit_FIDBRA(UChar *p, UChar m3, UChar m4, UChar r1, UChar r2)
 {
    vassert(m3 == 0 || s390_host_has_fpext);
 
-   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM)) {
-      if (m4 == 0)
-         S390_DISASM(MNM("fidbr"), FPR(r1), UINT(m3), FPR(r2));
-      else
-         S390_DISASM(MNM("fidbra"), FPR(r1), UINT(m3), FPR(r2), UINT(m4));
-   }
+   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM))
+      S390_DISASM(XMNM("fidbra", fp_convt_disasm), FPR(r1), MASK(m3), FPR(r2), MASK(m4));
 
    return emit_RRF2(p, 0xb35f0000, m3, m4, r1, r2);
 }
@@ -4465,12 +4445,8 @@ s390_emit_FIXBRA(UChar *p, UChar m3, UChar m4, UChar r1, UChar r2)
 {
    vassert(m3 == 0 || s390_host_has_fpext);
 
-   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM)) {
-      if (m4 == 0)
-         S390_DISASM(MNM("fixbr"), FPR(r1), UINT(m3), FPR(r2));
-      else
-         S390_DISASM(MNM("fixbra"), FPR(r1), UINT(m3), FPR(r2), UINT(m4));
-   }
+   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM))
+      S390_DISASM(XMNM("fixbra", fp_convt_disasm), FPR(r1), MASK(m3), FPR(r2), MASK(m4));
 
    return emit_RRF2(p, 0xb3470000, m3, m4, r1, r2);
 }
@@ -4611,12 +4587,8 @@ s390_emit_ADTRA(UChar *p, UChar r3, UChar m4, UChar r1, UChar r2)
 {
    vassert(s390_host_has_dfp);
    vassert(m4 == 0 || s390_host_has_fpext);
-   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM)) {
-      if (m4 == 0)
-         S390_DISASM(MNM("adtr"), FPR(r1), FPR(r2), FPR(r3));
-      else
-         S390_DISASM(MNM("adtra"), FPR(r1), FPR(r2), FPR(r3), UINT(m4));
-   }
+   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM))
+      S390_DISASM(XMNM("adtra", adtra_like_disasm), FPR(r1), FPR(r2), FPR(r3), MASK(m4));
 
    return emit_RRF4(p, 0xb3d20000, r3, m4, r1, r2);
 }
@@ -4627,12 +4599,8 @@ s390_emit_AXTRA(UChar *p, UChar r3, UChar m4, UChar r1, UChar r2)
 {
    vassert(s390_host_has_dfp);
    vassert(m4 == 0 || s390_host_has_fpext);
-   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM)) {
-      if (m4 == 0)
-         S390_DISASM(MNM("axtr"), FPR(r1), FPR(r2), FPR(r3));
-      else
-         S390_DISASM(MNM("axtra"), FPR(r1), FPR(r2), FPR(r3), UINT(m4));
-   }
+   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM))
+      S390_DISASM(XMNM("axtra", adtra_like_disasm), FPR(r1), FPR(r2), FPR(r3), MASK(m4));
 
    return emit_RRF4(p, 0xb3da0000, r3, m4, r1, r2);
 }
@@ -4911,12 +4879,8 @@ s390_emit_DDTRA(UChar *p, UChar r3, UChar m4, UChar r1, UChar r2)
 {
    vassert(s390_host_has_dfp);
    vassert(m4 == 0 || s390_host_has_fpext);
-   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM)) {
-      if (m4 == 0)
-         S390_DISASM(MNM("ddtr"), FPR(r1), FPR(r2), FPR(r3));
-      else
-         S390_DISASM(MNM("ddtra"), FPR(r1), FPR(r2), FPR(r3), UINT(m4));
-   }
+   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM))
+      S390_DISASM(XMNM("ddtra", adtra_like_disasm), FPR(r1), FPR(r2), FPR(r3), MASK(m4));
 
    return emit_RRF4(p, 0xb3d10000, r3, m4, r1, r2);
 }
@@ -4927,12 +4891,8 @@ s390_emit_DXTRA(UChar *p, UChar r3, UChar m4, UChar r1, UChar r2)
 {
    vassert(s390_host_has_dfp);
    vassert(m4 == 0 || s390_host_has_fpext);
-   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM)) {
-      if (m4 == 0)
-         S390_DISASM(MNM("dxtr"), FPR(r1), FPR(r2), FPR(r3));
-      else
-         S390_DISASM(MNM("dxtra"), FPR(r1), FPR(r2), FPR(r3), UINT(m4));
-   }
+   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM))
+      S390_DISASM(XMNM("dxtra", adtra_like_disasm), FPR(r1), FPR(r2), FPR(r3), MASK(m4));
 
    return emit_RRF4(p, 0xb3d90000, r3, m4, r1, r2);
 }
@@ -5028,7 +4988,7 @@ s390_emit_LEDTR(UChar *p, UChar m3, UChar m4, UChar r1, UChar r2)
    vassert(s390_host_has_fpext || m3 < 1 || m3 > 7);
 
    if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM))
-      S390_DISASM(MNM("ledtr"), FPR(r1), UINT(m3), FPR(r2), UINT(m4));
+      S390_DISASM(XMNM("ledtr", fp_convf_disasm), FPR(r1), MASK(m3), FPR(r2), MASK(m4));
 
    return emit_RRF2(p, 0xb3d50000, m3, m4, r1, r2);
 }
@@ -5042,7 +5002,7 @@ s390_emit_LDXTR(UChar *p, UChar m3, UChar m4, UChar r1, UChar r2)
    vassert(s390_host_has_fpext || m3 < 1 || m3 > 7);
 
    if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM))
-      S390_DISASM(MNM("ldxtr"), FPR(r1), UINT(m3), FPR(r2), UINT(m4));
+      S390_DISASM(XMNM("ldxtr", fp_convf_disasm), FPR(r1), MASK(m3), FPR(r2), MASK(m4));
 
    return emit_RRF2(p, 0xb3dd0000, m3, m4, r1, r2);
 }
@@ -5053,12 +5013,8 @@ s390_emit_MDTRA(UChar *p, UChar r3, UChar m4, UChar r1, UChar r2)
 {
    vassert(s390_host_has_dfp);
    vassert(m4 == 0 || s390_host_has_fpext);
-   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM)) {
-      if (m4 == 0)
-         S390_DISASM(MNM("mdtr"), FPR(r1), FPR(r2), FPR(r3));
-      else
-         S390_DISASM(MNM("mdtra"), FPR(r1), FPR(r2), FPR(r3), UINT(m4));
-   }
+   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM))
+      S390_DISASM(XMNM("mdtra", adtra_like_disasm), FPR(r1), FPR(r2), FPR(r3), MASK(m4));
 
    return emit_RRF4(p, 0xb3d00000, r3, m4, r1, r2);
 }
@@ -5069,12 +5025,8 @@ s390_emit_MXTRA(UChar *p, UChar r3, UChar m4, UChar r1, UChar r2)
 {
    vassert(s390_host_has_dfp);
    vassert(m4 == 0 || s390_host_has_fpext);
-   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM)) {
-      if (m4 == 0)
-         S390_DISASM(MNM("mxtr"), FPR(r1), FPR(r2), FPR(r3));
-      else
-         S390_DISASM(MNM("mxtra"), FPR(r1), FPR(r2), FPR(r3), UINT(m4));
-   }
+   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM))
+      S390_DISASM(XMNM("mxtra", adtra_like_disasm), FPR(r1), FPR(r2), FPR(r3), MASK(m4));
 
    return emit_RRF4(p, 0xb3d80000, r3, m4, r1, r2);
 }
@@ -5150,12 +5102,8 @@ s390_emit_SDTRA(UChar *p, UChar r3, UChar m4, UChar r1, UChar r2)
 {
    vassert(s390_host_has_dfp);
    vassert(m4 == 0 || s390_host_has_fpext);
-   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM)) {
-      if (m4 == 0)
-         S390_DISASM(MNM("sdtr"), FPR(r1), FPR(r2), FPR(r3));
-      else
-         S390_DISASM(MNM("sdtra"), FPR(r1), FPR(r2), FPR(r3), UINT(m4));
-   }
+   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM))
+      S390_DISASM(XMNM("sdtra", adtra_like_disasm), FPR(r1), FPR(r2), FPR(r3), MASK(m4));
 
    return emit_RRF4(p, 0xb3d30000, r3, m4, r1, r2);
 }
@@ -5166,12 +5114,8 @@ s390_emit_SXTRA(UChar *p, UChar r3, UChar m4, UChar r1, UChar r2)
 {
    vassert(s390_host_has_dfp);
    vassert(m4 == 0 || s390_host_has_fpext);
-   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM)) {
-      if (m4 == 0)
-         S390_DISASM(MNM("sxtr"), FPR(r1), FPR(r2), FPR(r3));
-      else
-         S390_DISASM(MNM("sxtra"), FPR(r1), FPR(r2), FPR(r3), UINT(m4));
-   }
+   if (UNLIKELY(vex_traceflags & VEX_TRACE_ASM))
+      S390_DISASM(XMNM("sxtra", adtra_like_disasm), FPR(r1), FPR(r2), FPR(r3), MASK(m4));
 
    return emit_RRF4(p, 0xb3db0000, r3, m4, r1, r2);
 }
diff --git a/VEX/priv/s390_disasm.c b/VEX/priv/s390_disasm.c
index 9649f9f0e1..139e141990 100644
--- a/VEX/priv/s390_disasm.c
+++ b/VEX/priv/s390_disasm.c
@@ -1066,6 +1066,24 @@ fp_convt_disasm(const s390_opnd *opnds, HChar *p)
 }
 
 
+HChar *
+adtra_like_disasm(const s390_opnd *opnds, HChar *p)
+{
+   const HChar *base = opnds[0].xmnm.base;
+   UInt m4 = opnds[get_mask_index(opnds, 1)].mask;
+   UInt len = vex_strlen(base);
+
+   HChar xmnm[len + 1];
+
+   vex_sprintf(xmnm, "%s", base);
+
+   if (xmnm[len - 1] == 'a' && m4 == 0) {
+      xmnm[len - 1] = '\0';
+   }
+   return s390_disasm_aux(opnds, xmnm, p, mask0_mh);
+}
+
+
 /* Write out OPNDS. MH is a mask handler. It decides whether or not a
    MASK operand is written and if so, massages the mask value as needed. */
 static HChar *
diff --git a/VEX/priv/s390_disasm.h b/VEX/priv/s390_disasm.h
index b28af8f659..f84f5061f6 100644
--- a/VEX/priv/s390_disasm.h
+++ b/VEX/priv/s390_disasm.h
@@ -137,6 +137,7 @@ HChar *vfce_like_disasm(const s390_opnd *, HChar *);
 HChar *vfmix_like_disasm(const s390_opnd *, HChar *);
 HChar *fp_convf_disasm(const s390_opnd *, HChar *);
 HChar *fp_convt_disasm(const s390_opnd *, HChar *);
+HChar *adtra_like_disasm(const s390_opnd *, HChar *);
 
 /*---------------------------------------------------------------*/
 /*--- end                                       s390_disasm.h ---*/


