Implement is-zero assign scope variables

lambdaclass · Oct 2, 2023 · a1ba3b1 · a1ba3b1
1 parent f418046
commit a1ba3b1
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Showing 4 changed files with 50 additions and 0 deletions.
diff --git a/pkg/hints/hint_codes/secp_hint_codes.go b/pkg/hints/hint_codes/secp_hint_codes.go
@@ -50,3 +50,8 @@ x = pack(ids.x, PRIME) % SECP_P`
 
 const IS_ZERO_PACK_V2 = `from starkware.cairo.common.cairo_secp.secp_utils import SECP_P, pack
 x = pack(ids.x, PRIME) % SECP_P`
+
+const IS_ZERO_ASSIGN_SCOPE_VARS = `from starkware.cairo.common.cairo_secp.secp_utils import SECP_P
+from starkware.python.math_utils import div_mod
+
+value = x_inv = div_mod(1, x, SECP_P)`
diff --git a/pkg/hints/hint_processor.go b/pkg/hints/hint_processor.go
@@ -227,6 +227,8 @@ func (p *CairoVmHintProcessor) ExecuteHint(vm *vm.VirtualMachine, hintData *any,
 		return isZeroNondet(data.Ids, vm)
 	case IS_ZERO_PACK_V1, IS_ZERO_PACK_V2:
 		return isZeroPack(data.Ids, vm, execScopes)
+	case IS_ZERO_ASSIGN_SCOPE_VARS:
+		return isZeroAssignScopeVars(execScopes)
 	default:
 		return errors.Errorf("Unknown Hint: %s", data.Code)
 	}

diff --git a/pkg/hints/secp_hints.go b/pkg/hints/secp_hints.go
@@ -6,6 +6,7 @@ import (
 	. "github.com/lambdaclass/cairo-vm.go/pkg/hints/hint_utils"
 	"github.com/lambdaclass/cairo-vm.go/pkg/lambdaworks"
 	. "github.com/lambdaclass/cairo-vm.go/pkg/types"
+	"github.com/lambdaclass/cairo-vm.go/pkg/utils"
 	. "github.com/lambdaclass/cairo-vm.go/pkg/vm"
 	"github.com/lambdaclass/cairo-vm.go/pkg/vm/memory"
 	"github.com/pkg/errors"
@@ -106,3 +107,19 @@ func isZeroPack(ids IdsManager, vm *VirtualMachine, scopes *ExecutionScopes) err
 	scopes.AssignOrUpdateVariable("x", *xModP)
 	return nil
 }
+
+func isZeroAssignScopeVars(scopes *ExecutionScopes) error {
+	secpP := SECP_P()
+	scopes.AssignOrUpdateVariable("SECP_P", secpP)
+	x, err := FetchScopeVar[big.Int]("x", scopes)
+	if err != nil {
+		return err
+	}
+	value, err := utils.DivMod(big.NewInt(1), &x, &secpP)
+	if err != nil {
+		return err
+	}
+	scopes.AssignOrUpdateVariable("value", *value)
+	scopes.AssignOrUpdateVariable("x_inv", *value)
+	return nil
+}
diff --git a/pkg/hints/secp_hints_test.go b/pkg/hints/secp_hints_test.go
@@ -344,3 +344,29 @@ func TestIsZeroPack(t *testing.T) {
 	xUnpacked := Uint384{Limbs: []Felt{FeltFromUint(6), FeltFromUint(6), FeltFromUint(6)}}
 	CheckScopeVar[big.Int]("x", xUnpacked.Pack86(), scopes, t)
 }
+
+func TestIsZeroAssignScopeVars(t *testing.T) {
+	vm := NewVirtualMachine()
+	vm.Segments.AddSegment()
+	idsManager := SetupIdsForTest(map[string][]*MaybeRelocatable{}, vm)
+
+	hintProcessor := CairoVmHintProcessor{}
+	hintData := any(HintData{
+		Ids:  idsManager,
+		Code: IS_ZERO_ASSIGN_SCOPE_VARS,
+	})
+	scopes := NewExecutionScopes()
+	x, _ := new(big.Int).SetString("52621538839140286024584685587354966255185961783273479086367", 10)
+	scopes.AssignOrUpdateVariable("x", *x)
+
+	err := hintProcessor.ExecuteHint(vm, &hintData, nil, scopes)
+	if err != nil {
+		t.Errorf("IS_ZERO_ASSIGN_SCOPE_VARS hint failed with error %s", err)
+	}
+	// Check scope vars
+	CheckScopeVar[big.Int]("SECP_P", SECP_P(), scopes, t)
+
+	value, _ := new(big.Int).SetString("19429627790501903254364315669614485084365347064625983303617500144471999752609", 10)
+	CheckScopeVar[big.Int]("value", *value, scopes, t)
+	CheckScopeVar[big.Int]("x_inv", *value, scopes, t)
+}