ARM: Implement conversion to/from half precision.

2 files changed, 86 insertions, 2 deletions

diff --git a/src/arch/arm/isa/formats/fp.isa b/src/arch/arm/isa/formats/fp.isa
index d509fc28a..03e574648 100644
--- a/src/arch/arm/isa/formats/fp.isa
+++ b/src/arch/arm/isa/formats/fp.isa
@@ -655,8 +655,23 @@ let {{
                 }
               case 0x2:
               case 0x3:
-                // Between half and single precision.
-                return new WarnUnimplemented("vcvtb, vcvtt", machInst);
+                {
+                    const bool toHalf = bits(machInst, 16);
+                    const bool top = bits(machInst, 7);
+                    if (top) {
+                        if (toHalf) {
+                            return new VcvtFpSFpHT(machInst, vd, vm);
+                        } else {
+                            return new VcvtFpHTFpS(machInst, vd, vm);
+                        }
+                    } else {
+                        if (toHalf) {
+                            return new VcvtFpSFpHB(machInst, vd, vm);
+                        } else {
+                            return new VcvtFpHBFpS(machInst, vd, vm);
+                        }
+                    }
+                }
               case 0x4:
                 if (single) {
                     if (e) {
diff --git a/src/arch/arm/isa/insts/fp.isa b/src/arch/arm/isa/insts/fp.isa
index bee63d671..c4682b66c 100644
--- a/src/arch/arm/isa/insts/fp.isa
+++ b/src/arch/arm/isa/insts/fp.isa
@@ -912,6 +912,75 @@ let {{
     decoder_output += FpRegRegOpConstructor.subst(vcvtFpDFpSIop);
     exec_output += PredOpExecute.subst(vcvtFpDFpSIop);
 
+    vcvtFpHTFpSCode = '''
+        FPSCR fpscr = Fpscr;
+        vfpFlushToZero(fpscr, FpOp1);
+        VfpSavedState state = prepFpState(fpscr.rMode);
+        __asm__ __volatile__("" : "=m" (FpOp1) : "m" (FpOp1));
+        FpDest = vcvtFpHFpS(fpscr, FpOp1, true);
+        __asm__ __volatile__("" :: "m" (FpDest));
+        finishVfp(fpscr, state);
+        Fpscr = fpscr;
+    '''
+    vcvtFpHTFpSIop = InstObjParams("vcvtt", "VcvtFpHTFpS", "FpRegRegOp",
+                                   { "code": vcvtFpHTFpSCode,
+                                     "predicate_test": predicateTest }, [])
+    header_output += FpRegRegOpDeclare.subst(vcvtFpHTFpSIop);
+    decoder_output += FpRegRegOpConstructor.subst(vcvtFpHTFpSIop);
+    exec_output += PredOpExecute.subst(vcvtFpHTFpSIop);
+
+    vcvtFpHBFpSCode = '''
+        FPSCR fpscr = Fpscr;
+        VfpSavedState state = prepFpState(fpscr.rMode);
+        __asm__ __volatile__("" : "=m" (FpOp1) : "m" (FpOp1));
+        FpDest = vcvtFpHFpS(fpscr, FpOp1, false);
+        __asm__ __volatile__("" :: "m" (FpDest));
+        finishVfp(fpscr, state);
+        Fpscr = fpscr;
+    '''
+    vcvtFpHBFpSIop = InstObjParams("vcvtb", "VcvtFpHBFpS", "FpRegRegOp",
+                                   { "code": vcvtFpHBFpSCode,
+                                     "predicate_test": predicateTest }, [])
+    header_output += FpRegRegOpDeclare.subst(vcvtFpHBFpSIop);
+    decoder_output += FpRegRegOpConstructor.subst(vcvtFpHBFpSIop);
+    exec_output += PredOpExecute.subst(vcvtFpHBFpSIop);
+
+    vcvtFpSFpHTCode = '''
+        FPSCR fpscr = Fpscr;
+        vfpFlushToZero(fpscr, FpOp1);
+        VfpSavedState state = prepFpState(fpscr.rMode);
+        __asm__ __volatile__("" : "=m" (FpOp1), "=m" (FpDest)
+                                : "m" (FpOp1), "m" (FpDest));
+        FpDest = vcvtFpSFpH(fpscr, FpOp1, FpDest, true);
+        __asm__ __volatile__("" :: "m" (FpDest));
+        finishVfp(fpscr, state);
+        Fpscr = fpscr;
+    '''
+    vcvtFpSFpHTIop = InstObjParams("vcvtt", "VcvtFpSFpHT", "FpRegRegOp",
+                                    { "code": vcvtFpHTFpSCode,
+                                      "predicate_test": predicateTest }, [])
+    header_output += FpRegRegOpDeclare.subst(vcvtFpSFpHTIop);
+    decoder_output += FpRegRegOpConstructor.subst(vcvtFpSFpHTIop);
+    exec_output += PredOpExecute.subst(vcvtFpSFpHTIop);
+
+    vcvtFpSFpHBCode = '''
+        FPSCR fpscr = Fpscr;
+        vfpFlushToZero(fpscr, FpOp1);
+        VfpSavedState state = prepFpState(fpscr.rMode);
+        __asm__ __volatile__("" : "=m" (FpOp1), "=m" (FpDest)
+                                : "m" (FpOp1), "m" (FpDest));
+        FpDest = vcvtFpSFpH(fpscr, FpOp1, FpDest, false);
+        __asm__ __volatile__("" :: "m" (FpDest));
+        finishVfp(fpscr, state);
+        Fpscr = fpscr;
+    '''
+    vcvtFpSFpHBIop = InstObjParams("vcvtb", "VcvtFpSFpHB", "FpRegRegOp",
+                                   { "code": vcvtFpSFpHBCode,
+                                     "predicate_test": predicateTest }, [])
+    header_output += FpRegRegOpDeclare.subst(vcvtFpSFpHBIop);
+    decoder_output += FpRegRegOpConstructor.subst(vcvtFpSFpHBIop);
+    exec_output += PredOpExecute.subst(vcvtFpSFpHBIop);
+
     vcmpSCode = '''
         FPSCR fpscr = Fpscr;
         vfpFlushToZero(fpscr, FpDest, FpOp1);