+
+ /// getT2SOImmValSplat - Return the 12-bit encoded representation
+ /// if the specified value can be obtained by splatting the low 8 bits
+ /// into every other byte or every byte of a 32-bit value. i.e.,
+ /// 00000000 00000000 00000000 abcdefgh control = 0
+ /// 00000000 abcdefgh 00000000 abcdefgh control = 1
+ /// abcdefgh 00000000 abcdefgh 00000000 control = 2
+ /// abcdefgh abcdefgh abcdefgh abcdefgh control = 3
+ /// Return -1 if none of the above apply.
+ /// See ARM Reference Manual A6.3.2.
+ static inline int getT2SOImmValSplatVal(unsigned V) {
+ unsigned u, Vs, Imm;
+ // control = 0
+ if ((V & 0xffffff00) == 0)
+ return V;
+
+ // If the value is zeroes in the first byte, just shift those off
+ Vs = ((V & 0xff) == 0) ? V >> 8 : V;
+ // Any passing value only has 8 bits of payload, splatted across the word
+ Imm = Vs & 0xff;
+ // Likewise, any passing values have the payload splatted into the 3rd byte
+ u = Imm | (Imm << 16);
+
+ // control = 1 or 2
+ if (Vs == u)
+ return (((Vs == V) ? 1 : 2) << 8) | Imm;
+
+ // control = 3
+ if (Vs == (u | (u << 8)))
+ return (3 << 8) | Imm;
+
+ return -1;
+ }
+
+ /// getT2SOImmValRotateVal - Return the 12-bit encoded representation if the
+ /// specified value is a rotated 8-bit value. Return -1 if no rotation
+ /// encoding is possible.
+ /// See ARM Reference Manual A6.3.2.
+ static inline int getT2SOImmValRotateVal(unsigned V) {
+ unsigned RotAmt = CountLeadingZeros_32(V);
+ if (RotAmt >= 24)
+ return -1;
+
+ // If 'Arg' can be handled with a single shifter_op return the value.
+ if ((rotr32(0xff000000U, RotAmt) & V) == V)
+ return (rotr32(V, 24 - RotAmt) & 0x7f) | ((RotAmt + 8) << 7);
+
+ return -1;
+ }
+
+ /// getT2SOImmVal - Given a 32-bit immediate, if it is something that can fit
+ /// into a Thumb-2 shifter_operand immediate operand, return the 12-bit
+ /// encoding for it. If not, return -1.
+ /// See ARM Reference Manual A6.3.2.
+ static inline int getT2SOImmVal(unsigned Arg) {
+ // If 'Arg' is an 8-bit splat, then get the encoded value.
+ int Splat = getT2SOImmValSplatVal(Arg);
+ if (Splat != -1)
+ return Splat;
+
+ // If 'Arg' can be handled with a single shifter_op return the value.
+ int Rot = getT2SOImmValRotateVal(Arg);
+ if (Rot != -1)
+ return Rot;
+
+ return -1;
+ }
+
+ static inline unsigned getT2SOImmValRotate(unsigned V) {
+ if ((V & ~255U) == 0) return 0;
+ // Use CTZ to compute the rotate amount.
+ unsigned RotAmt = CountTrailingZeros_32(V);
+ return (32 - RotAmt) & 31;
+ }
+
+ static inline bool isT2SOImmTwoPartVal (unsigned Imm) {
+ unsigned V = Imm;
+ // Passing values can be any combination of splat values and shifter
+ // values. If this can be handled with a single shifter or splat, bail
+ // out. Those should be handled directly, not with a two-part val.
+ if (getT2SOImmValSplatVal(V) != -1)
+ return false;
+ V = rotr32 (~255U, getT2SOImmValRotate(V)) & V;
+ if (V == 0)
+ return false;
+
+ // If this can be handled as an immediate, accept.
+ if (getT2SOImmVal(V) != -1) return true;
+
+ // Likewise, try masking out a splat value first.
+ V = Imm;
+ if (getT2SOImmValSplatVal(V & 0xff00ff00U) != -1)
+ V &= ~0xff00ff00U;
+ else if (getT2SOImmValSplatVal(V & 0x00ff00ffU) != -1)
+ V &= ~0x00ff00ffU;
+ // If what's left can be handled as an immediate, accept.
+ if (getT2SOImmVal(V) != -1) return true;
+
+ // Otherwise, do not accept.
+ return false;
+ }
+
+ static inline unsigned getT2SOImmTwoPartFirst(unsigned Imm) {
+ assert (isT2SOImmTwoPartVal(Imm) &&
+ "Immedate cannot be encoded as two part immediate!");
+ // Try a shifter operand as one part
+ unsigned V = rotr32 (~255, getT2SOImmValRotate(Imm)) & Imm;
+ // If the rest is encodable as an immediate, then return it.
+ if (getT2SOImmVal(V) != -1) return V;
+
+ // Try masking out a splat value first.
+ if (getT2SOImmValSplatVal(Imm & 0xff00ff00U) != -1)
+ return Imm & 0xff00ff00U;
+
+ // The other splat is all that's left as an option.
+ assert (getT2SOImmValSplatVal(Imm & 0x00ff00ffU) != -1);
+ return Imm & 0x00ff00ffU;
+ }
+
+ static inline unsigned getT2SOImmTwoPartSecond(unsigned Imm) {
+ // Mask out the first hunk
+ Imm ^= getT2SOImmTwoPartFirst(Imm);
+ // Return what's left
+ assert (getT2SOImmVal(Imm) != -1 &&
+ "Unable to encode second part of T2 two part SO immediate");
+ return Imm;
+ }
+
+