exec: implement NewMinList

SFS initializes a large set of MinList structures during startup.\nThe rebased tree left NewMinList() as a missing exec.library stub,\nso those list heads never became valid and later startup work fell\napart.\n\nInitialize the MinList header in place and cover it with a pytask\nregression test.

Author: reinauer

amitools/vamos/lib/ExecLibrary.py

@@ -7,6 +7,7 @@
     ExecLibraryStruct,
     StackSwapStruct,
     IORequestStruct,
+    MinListStruct,
     MsgPortStruct,
     NodeType,
     SignalSemaphoreStruct,
@@ -652,6 +653,22 @@ def WaitIO(self, ctx):
 
     # ----- Nodes/Lists -----
 
+    def NewMinList(self, ctx):
+        minlist_addr = ctx.cpu.r_reg(REG_A0)
+        minlist = AccessStruct(ctx.mem, MinListStruct, minlist_addr)
+        head_off = MinListStruct.sdef.find_field_def_by_name("mlh_Head").offset
+        tail_off = MinListStruct.sdef.find_field_def_by_name("mlh_Tail").offset
+        tailpred_off = MinListStruct.sdef.find_field_def_by_name(
+            "mlh_TailPred"
+        ).offset
+        head_addr = minlist_addr + head_off
+        tail_addr = minlist_addr + tail_off
+        minlist.w_s("mlh_Head", tail_addr)
+        minlist.w_s("mlh_Tail", 0)
+        minlist.w_s("mlh_TailPred", head_addr)
+        log_exec.info("NewMinList(0x%06x)", minlist_addr)
+        return minlist_addr
+
     def AddTail(self, ctx, list: List, node: Node):
         log_exec.info("AddTail(%s, %s)", list, node)
         list.add_tail(node)

test/pytask/pytask_exec_list.py

@@ -1,6 +1,6 @@
 import pytest
 from amitools.vamos.libtypes import List, Node
-from amitools.vamos.libstructs import NodeType
+from amitools.vamos.libstructs import MinListStruct, NodeType
 
 
 def pytask_exec_list_alloc_free_test(vamos_task):
@@ -23,6 +23,33 @@ def task(ctx, task):
     assert exit_codes == [0]
 
 
+def pytask_exec_list_new_min_list_test(vamos_task):
+    def task(ctx, task):
+        exec_lib = ctx.proxies.get_exec_lib_proxy()
+
+        minlist_mem = ctx.alloc.alloc_struct(MinListStruct)
+        exec_lib.NewMinList(minlist_mem.addr)
+
+        head_off = MinListStruct.sdef.find_field_def_by_name("mlh_Head").offset
+        tail_off = MinListStruct.sdef.find_field_def_by_name("mlh_Tail").offset
+        tailpred_off = MinListStruct.sdef.find_field_def_by_name(
+            "mlh_TailPred"
+        ).offset
+
+        assert ctx.mem.r32(minlist_mem.addr + head_off) == minlist_mem.addr + tail_off
+        assert ctx.mem.r32(minlist_mem.addr + tail_off) == 0
+        assert (
+            ctx.mem.r32(minlist_mem.addr + tailpred_off)
+            == minlist_mem.addr + head_off
+        )
+
+        ctx.alloc.free_struct(minlist_mem)
+        return 0
+
+    exit_codes = vamos_task.run([task])
+    assert exit_codes == [0]
+
+
 class ListHelper:
     def __init__(self, alloc):
         self.list = List.alloc(alloc)