first version of kmemcpy5/kmemset4

include/util/kmemset4_func.nasm

@@ -0,0 +1,47 @@
+; Copyright (c) 2024 Elaina Claus
+;
+; Permission is hereby granted, free of charge, to any person obtaining a copy
+; of this software and associated documentation files (the "Software"), to deal
+; in the Software without restriction, including without limitation the rights
+; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+; copies of the Software, and to permit persons to whom the Software is
+; furnished to do so, subject to the following conditions:
+;
+; The above copyright notice and this permission notice shall be included in all
+; copies or substantial portions of the Software.
+;
+; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+; SOFTWARE.
+
+%ifndef __INC_KMEMSET4_FUNC
+%include 'cdecl16.inc'
+
+; word kmemset_byte(word segment, word dst, byte val, word len);
+ALIGN 4, db 0x90
+kmemset4:
+    __CDECL16_ENTRY
+.setup_segment:
+    push es
+    mov ax, [bp + 4]
+    mov es, ax
+ .func:
+    mov     cx, [bp + 10]       ; size_t len
+    mov     al, [bp + 8]        ; uint8_t val
+    mov     di, [bp + 6]        ; word dst
+
+    cld
+    rep     stosb               ; move al -> es:di
+    mov     ax, di              ; return pointer to dest
+.restore_segments:
+    pop es
+.endf:
+    __CDECL16_EXIT
+    ret
+
+%endif
+%define __INC_KMEMSET4_FUNC