Add x86_64 kernel bring-up with build-selected platform adapters

src/arch/x86/platform/arch.platform.cpu.pas

@@ -0,0 +1,53 @@
+// Copyright 2026 Aaron Hance
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+{ Build-selected x86 adapter. }
+unit arch.platform.cpu;
+interface
+{$i ../../common/platform.cpu.inc}
+implementation
+uses arch.x86.util, memory.raw;
+function lock: PtrUInt; assembler; nostackframe;
+asm pushfd; cli; pop eax end;
+procedure unlock(flags: PtrUInt);
+begin if (flags and $200) <> 0 then asm sti end; end;
+procedure idle;
+begin asm hlt end; end;
+procedure outb(port: uint16; value: uint8);
+begin arch.x86.util.outb(port, value); end;
+function inb(port: uint16): uint8;
+begin inb := arch.x86.util.inb(port); end;
+procedure copyBytes(source, dest: PtrUInt; bytes: SizeUInt);
+begin
+    if bytes >= 16 then arch.x86.util.__REP_MOVSB_memcpy(source, dest, bytes)
+    else memory.raw.move(pointer(source), pointer(dest), bytes);
+end;
+procedure zero(dest: pointer; bytes: SizeUInt);
+var d: pointer; b: SizeUInt;
+begin
+    d := dest; b := bytes;
+    if b = 0 then exit;
+    asm
+        push edi
+        mov edi, d
+        mov ecx, b
+        shr ecx, 2
+        xor eax, eax
+        cld
+        rep stosd
+        mov ecx, b
+        and ecx, 3
+        rep stosb
+        pop edi
+    end;
+end;
+end.