Initial commit

common/ndsabi/memset.s

@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: Zlib
+// SPDX-FileNotice: Modified from the original version by the BlocksDS project.
+//
+// Copyright (C) 2021-2023 agbabi contributors
+//
+// ABI:
+//    __aeabi_memclr, __aeabi_memclr4, __aeabi_memclr8,
+//    __aeabi_memset, __aeabi_memset4, __aeabi_memset8
+// Standard:
+//    memset
+// Support:
+//    __ndsabi_wordset4, __ndsabi_lwordset4, __ndsabi_memset1
+
+#include <nds/asminc.h>
+
+#include "macros.inc"
+
+    .syntax unified
+
+    .arm
+
+
+BEGIN_ASM_FUNC __aeabi_memclr
+
+    mov     r2, #0
+    b       __aeabi_memset
+
+
+BEGIN_ASM_FUNC __aeabi_memclr8
+BEGIN_ASM_FUNC_NO_SECTION __aeabi_memclr4
+
+    mov     r2, #0
+    b       __ndsabi_wordset4
+
+
+BEGIN_ASM_FUNC __aeabi_memset
+
+    @ < 8 bytes probably won't be aligned: go byte-by-byte
+    cmp     r1, #8
+    blt     __ndsabi_memset1
+
+    @ Copy head to align to next word
+    rsb     r3, r0, #4
+    joaobapt_test r3
+    strbmi  r2, [r0], #1
+    submi   r1, r1, #1
+    strbcs  r2, [r0], #1
+    strbcs  r2, [r0], #1
+    subcs   r1, r1, #2
+
+BEGIN_ASM_FUNC_NO_SECTION __aeabi_memset8
+BEGIN_ASM_FUNC_NO_SECTION __aeabi_memset4
+
+    lsl     r2, r2, #24
+    orr     r2, r2, r2, lsr #8
+    orr     r2, r2, r2, lsr #16
+
+BEGIN_ASM_FUNC_NO_SECTION __ndsabi_wordset4
+
+    mov     r3, r2
+
+BEGIN_ASM_FUNC_NO_SECTION __ndsabi_lwordset4
+
+    @ 16 words is roughly the threshold when lwordset is slower
+    cmp     r1, #64
+    blt     .Lset_2_words
+
+    @ 8 word set
+    push    {r4-r9}
+    mov     r4, r2
+    mov     r5, r3
+    mov     r6, r2
+    mov     r7, r3
+    mov     r8, r2
+    mov     r9, r3
+
+.Lset_8_words:
+    subs    r1, r1, #32
+    stmiage r0!, {r2-r9}
+    bgt     .Lset_8_words
+    pop     {r4-r9}
+    bxeq    lr
+
+    @ Fixup remaining
+    add     r1, r1, #32
+.Lset_2_words:
+    subs    r1, r1, #8
+    stmiage r0!, {r2-r3}
+    bgt     .Lset_2_words
+    bxeq    lr
+
+    @ Test for remaining word
+    adds    r1, r1, #4
+    strge   r2, [r0], #4
+    bxeq    lr
+
+    @ Set tail
+    joaobapt_test r1
+    strhcs  r2, [r0], #2
+    strbmi  r2, [r0], #1
+    bx      lr
+
+
+BEGIN_ASM_FUNC __ndsabi_memset1
+
+    subs    r1, r1, #1
+    strbge  r2, [r0], #1
+    bgt     __ndsabi_memset1
+    bx      lr
+
+
+BEGIN_ASM_FUNC memset
+
+    mov     r3, r1
+    mov     r1, r2
+    mov     r2, r3
+    push    {r0, lr}
+    bl      __aeabi_memset
+    pop     {r0, lr}
+    bx      lr