diff options
| author | merry <git@mary.rs> | 2022-02-06 15:25:45 +0000 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2022-02-06 12:25:45 -0300 |
| commit | 88d3ffb97c9d6e29a7eb44135ccea88753ca5f61 (patch) | |
| tree | 448a5f7bd29cebc964bdaff87b23b34293406941 /ARMeilleure/Instructions | |
| parent | 222b1ad7da04830852664dbd465117e441211f28 (diff) | |
ARMeilleure: A32: Implement SHADD8 (#3086)1.1.18
Diffstat (limited to 'ARMeilleure/Instructions')
| -rw-r--r-- | ARMeilleure/Instructions/InstEmitAlu32.cs | 52 | ||||
| -rw-r--r-- | ARMeilleure/Instructions/InstName.cs | 1 |
2 files changed, 38 insertions, 15 deletions
diff --git a/ARMeilleure/Instructions/InstEmitAlu32.cs b/ARMeilleure/Instructions/InstEmitAlu32.cs index 5f55fcd1..9aff0261 100644 --- a/ARMeilleure/Instructions/InstEmitAlu32.cs +++ b/ARMeilleure/Instructions/InstEmitAlu32.cs @@ -387,6 +387,11 @@ namespace ARMeilleure.Instructions EmitDiv(context, false); } + public static void Shadd8(ArmEmitterContext context) + { + EmitHadd8(context, false); + } + public static void Ssat(ArmEmitterContext context) { OpCode32Sat op = (OpCode32Sat)context.CurrOp; @@ -474,20 +479,7 @@ namespace ARMeilleure.Instructions public static void Uhadd8(ArmEmitterContext context) { - OpCode32AluReg op = (OpCode32AluReg)context.CurrOp; - - Operand m = GetIntA32(context, op.Rm); - Operand n = GetIntA32(context, op.Rn); - - Operand xor, res; - - res = context.BitwiseAnd(m, n); - xor = context.BitwiseExclusiveOr(m, n); - xor = context.ShiftRightUI(xor, Const(1)); - xor = context.BitwiseAnd(xor, Const(0x7F7F7F7Fu)); - res = context.Add(res, xor); - - SetIntA32(context, op.Rd, res); + EmitHadd8(context, true); } public static void Usat(ArmEmitterContext context) @@ -659,6 +651,36 @@ namespace ARMeilleure.Instructions context.MarkLabel(lblEnd); } + private static void EmitHadd8(ArmEmitterContext context, bool unsigned) + { + OpCode32AluReg op = (OpCode32AluReg)context.CurrOp; + + Operand m = GetIntA32(context, op.Rm); + Operand n = GetIntA32(context, op.Rn); + + Operand xor, res, carry; + + // This relies on the equality x+y == ((x&y) << 1) + (x^y). + // Note that x^y always contains the LSB of the result. + // Since we want to calculate (x+y)/2, we can instead calculate (x&y) + ((x^y)>>1). + // We mask by 0x7F to remove the LSB so that it doesn't leak into the field below. + + res = context.BitwiseAnd(m, n); + carry = context.BitwiseExclusiveOr(m, n); + xor = context.ShiftRightUI(carry, Const(1)); + xor = context.BitwiseAnd(xor, Const(0x7F7F7F7Fu)); + res = context.Add(res, xor); + + if (!unsigned) + { + // Propagates the sign bit from (x^y)>>1 upwards by one. + carry = context.BitwiseAnd(carry, Const(0x80808080u)); + res = context.BitwiseExclusiveOr(res, carry); + } + + SetIntA32(context, op.Rd, res); + } + private static void EmitSat(ArmEmitterContext context, int intMin, int intMax) { OpCode32Sat op = (OpCode32Sat)context.CurrOp; @@ -772,4 +794,4 @@ namespace ARMeilleure.Instructions EmitGenericAluStoreA32(context, op.Rd, op.SetFlags, value); } } -}
\ No newline at end of file +} diff --git a/ARMeilleure/Instructions/InstName.cs b/ARMeilleure/Instructions/InstName.cs index a520c86a..698979b9 100644 --- a/ARMeilleure/Instructions/InstName.cs +++ b/ARMeilleure/Instructions/InstName.cs @@ -516,6 +516,7 @@ namespace ARMeilleure.Instructions Rsb, Rsc, Sbfx, + Shadd8, Smla__, Smlal, Smlal__, |