IsZeroPack Hint Implementation (#469)

* Implemented IsZeroPack Hint * Added Documentation * Update zerohint_signature.go * Update zerohint_signature.go * nits * nit * nit
NethermindEth · Jun 19, 2024 · 1153823 · 1153823
1 parent fc520ad
commit 1153823
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diff --git a/pkg/hintrunner/zero/hintcode.go b/pkg/hintrunner/zero/hintcode.go
@@ -104,6 +104,7 @@ const (
 	importSecp256R1PCode      string = "from starkware.cairo.common.cairo_secp.secp256r1_utils import SECP256R1_P as SECP_P"
 	verifyZeroCode            string = "from starkware.cairo.common.cairo_secp.secp_utils import SECP_P, pack\n\nq, r = divmod(pack(ids.val, PRIME), SECP_P)\nassert r == 0, f\"verify_zero: Invalid input {ids.val.d0, ids.val.d1, ids.val.d2}.\"\nids.q = q % PRIME"
 	divModNPackedDivmodV1Code string = "from starkware.cairo.common.cairo_secp.secp_utils import N, pack\nfrom starkware.python.math_utils import div_mod, safe_div\n\na = pack(ids.a, PRIME)\nb = pack(ids.b, PRIME)\nvalue = res = div_mod(a, b, N)"
+	isZeroPackCode            string = "from starkware.cairo.common.cairo_secp.secp_utils import SECP_P, pack\n\nx = pack(ids.x, PRIME) % SECP_P"
 
 	// ------ Blake Hash hints related code ------
 	blake2sAddUint256BigendCode string = "B = 32\nMASK = 2 ** 32 - 1\nsegments.write_arg(ids.data, [(ids.high >> (B * (3 - i))) & MASK for i in range(4)])\nsegments.write_arg(ids.data + 4, [(ids.low >> (B * (3 - i))) & MASK for i in range(4)])"

diff --git a/pkg/hintrunner/zero/zerohint.go b/pkg/hintrunner/zero/zerohint.go
@@ -122,6 +122,8 @@ func GetHintFromCode(program *zero.ZeroProgram, rawHint zero.Hint, hintPC uint64
 		return createVerifyZeroHinter(resolver)
 	case divModNPackedDivmodV1Code:
 		return createDivModNPackedDivmodV1Hinter(resolver)
+	case isZeroPackCode:
+		return createIsZeroPackHinter(resolver)
 	// EC hints
 	case ecNegateCode:
 		return createEcNegateHinter(resolver)

diff --git a/pkg/hintrunner/zero/zerohint_signature.go b/pkg/hintrunner/zero/zerohint_signature.go
@@ -386,3 +386,57 @@ func createDivModNPackedDivmodV1Hinter(resolver hintReferenceResolver) (hinter.H
 
 	return newDivModNPackedDivmodV1Hint(a, b), nil
 }
+
+// IsZeroPack hint computes packed value modulo SECP_P prime
+//
+// `newIsZeroPackHint` takes 1 operander as argument
+//   - `x` is the value that will be packed and taken modulo SECP_P prime
+//
+// `newIsZeroPackHint` assigns the result as `x` in the current scope
+func newIsZeroPackHint(x hinter.ResOperander) hinter.Hinter {
+	return &GenericZeroHinter{
+		Name: "IsZeroPack",
+		Op: func(vm *VM.VirtualMachine, ctx *hinter.HintRunnerContext) error {
+			//> from starkware.cairo.common.cairo_secp.secp_utils import SECP_P, pack
+			//> x = pack(ids.x, PRIME) % SECP_P
+
+			xAddr, err := x.GetAddress(vm)
+			if err != nil {
+				return err
+			}
+
+			xValues, err := vm.Memory.ResolveAsBigInt3(xAddr)
+			if err != nil {
+				return err
+			}
+
+			secPBig, ok := secp_utils.GetSecPBig()
+			if !ok {
+				return fmt.Errorf("GetSecPBig failed")
+			}
+
+			xPackedBig, err := secp_utils.SecPPacked(xValues)
+			if err != nil {
+				return err
+			}
+
+			value := new(big.Int)
+			value.Mod(&xPackedBig, &secPBig)
+
+			if err := ctx.ScopeManager.AssignVariable("x", value); err != nil {
+				return err
+			}
+
+			return nil
+		},
+	}
+}
+
+func createIsZeroPackHinter(resolver hintReferenceResolver) (hinter.Hinter, error) {
+	x, err := resolver.GetResOperander("x")
+	if err != nil {
+		return nil, err
+	}
+
+	return newIsZeroPackHint(x), nil
+}
diff --git a/pkg/hintrunner/zero/zerohint_signature_test.go b/pkg/hintrunner/zero/zerohint_signature_test.go
@@ -248,5 +248,51 @@ func TestVerifyZeroHint(t *testing.T) {
 				}),
 			},
 		},
+		"IsZeroPack": {
+			{
+				operanders: []*hintOperander{
+					{Name: "x.d0", Kind: apRelative, Value: feltString("42")},
+					{Name: "x.d1", Kind: apRelative, Value: feltString("0")},
+					{Name: "x.d2", Kind: apRelative, Value: feltString("0")},
+				},
+				makeHinter: func(ctx *hintTestContext) hinter.Hinter {
+					return newIsZeroPackHint(ctx.operanders["x.d0"])
+				},
+				check: varValueInScopeEquals("x", big.NewInt(42)),
+			},
+			{
+				operanders: []*hintOperander{
+					{Name: "x.d0", Kind: apRelative, Value: feltString("100")},
+					{Name: "x.d1", Kind: apRelative, Value: feltString("99")},
+					{Name: "x.d2", Kind: apRelative, Value: feltString("88")},
+				},
+				makeHinter: func(ctx *hintTestContext) hinter.Hinter {
+					return newIsZeroPackHint(ctx.operanders["x.d0"])
+				},
+				check: varValueInScopeEquals("x", bigIntString("526795342172649295060681798242672774947232024188944484", 10)),
+			},
+			{
+				operanders: []*hintOperander{
+					{Name: "x.d0", Kind: apRelative, Value: feltString("77371252455336262886226991")},
+					{Name: "x.d1", Kind: apRelative, Value: feltString("77371252455336267181195263")},
+					{Name: "x.d2", Kind: apRelative, Value: feltString("19342813113834066795298815")},
+				},
+				makeHinter: func(ctx *hintTestContext) hinter.Hinter {
+					return newIsZeroPackHint(ctx.operanders["x.d0"])
+				},
+				check: varValueInScopeEquals("x", big.NewInt(0)),
+			},
+			{
+				operanders: []*hintOperander{
+					{Name: "x.d0", Kind: apRelative, Value: feltString("3618502788666131213697322783095070105623107215331596699973092056135872020481")},
+					{Name: "x.d1", Kind: apRelative, Value: feltString("0")},
+					{Name: "x.d2", Kind: apRelative, Value: feltString("0")},
+				},
+				makeHinter: func(ctx *hintTestContext) hinter.Hinter {
+					return newIsZeroPackHint(ctx.operanders["x.d0"])
+				},
+				check: varValueInScopeEquals("x", big.NewInt(0)),
+			},
+		},
 	})
 }