syscall handler init

cairo0-bootloader/os/syscall_handler.py

@@ -0,0 +1,24 @@
+from typing import Iterable
+from starkware.starknet.core.os.syscall_handler import SyscallHandlerBase, OsExecutionHelper
+from starkware.cairo.lang.vm.relocatable import RelocatableValue, MaybeRelocatable
+from starkware.cairo.lang.vm.memory_segments import MemorySegmentManager
+
+class SyscallHandler(SyscallHandlerBase):
+    """
+    A handler for system calls; used by the BusinessLogic entry point execution.
+    """
+
+    def __init__(
+        self,
+        segments: MemorySegmentManager,
+    ):
+        super().__init__(segments=segments, initial_syscall_ptr=None)
+
+    def set_syscall_ptr(self, syscall_ptr: RelocatableValue):
+        assert self._syscall_ptr is None, "syscall_ptr is already set."
+        self._syscall_ptr = syscall_ptr
+
+    def allocate_segment(self, data: Iterable[MaybeRelocatable]) -> RelocatableValue:
+        segment_start = self.segments.add()
+        self.segments.write_arg(ptr=segment_start, arg=data)
+        return segment_start