Multiply-Add checked pointer multiplies two register values, adds a third register value, and writes the result to the destination register. The intermediate product is treated as the offset.
If the operation would have generated a result where the most significant 8 bits of the result register differ from the most significant 8 bits of the base register, then the result is modified such that it is likely to be non-canonical when used as an address.
If the intermediate product cannot be correctly represented as a 64-bit two's complement value, then the result is modified such that it is likely to be non-canonical when used as an address.
| 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| 1 | 0 | 0 | 1 | 1 | 0 | 1 | 1 | 0 | 1 | 1 | Rm | 0 | Ra | Rn | Rd | ||||||||||||||||
| sf | op54 | op31 | o0 | ||||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_CPA) then UNDEFINED; integer d = UInt(Rd); integer n = UInt(Rn); integer m = UInt(Rm); integer a = UInt(Ra);
| <Xd> |
Is the 64-bit name of the general-purpose destination register, encoded in the "Rd" field. |
| <Xn> |
Is the 64-bit name of the first general-purpose source register holding the multiplicand, encoded in the "Rn" field. |
| <Xm> |
Is the 64-bit name of the second general-purpose source register holding the multiplier, encoded in the "Rm" field. |
| <Xa> |
Is the 64-bit name of the third general-purpose source register holding the addend, encoded in the "Ra" field. |
bits(64) operand1 = X[n, 64]; bits(64) operand2 = X[m, 64]; bits(64) operand3 = X[a, 64]; bits(64) result; integer product = SInt(operand1) * SInt(operand2); // Signed and unsigned twos complement arithmetic are equivalent if only a // fixed number of bits are considered. result = operand3 + product<63:0>; boolean overflow = (product != SInt(product<63:0>)); result = PointerMultiplyAddCheck(result, operand3, overflow); X[d, 64] = result;
Internal version only: aarchmrs v2023-12_rel, pseudocode v2023-12_rel, sve v2023-12_rel ; Build timestamp: 2023-12-15T16:46
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