wrote apple-exit.c and s

section_1/funcs/apple-exit.c

@@ -0,0 +1,8 @@
+/*
+*/
+
+#include <stdlib.h>
+
+int main() {
+    exit(3510);
+}

section_1/funcs/apple-exit.s

@@ -0,0 +1,20 @@
+	.section	__TEXT,__text,regular,pure_instructions
+	.build_version macos, 14, 0	sdk_version 14, 2
+	.globl	_main                           ; -- Begin function main
+	.p2align	2
+_main:                                  ; @main
+	.cfi_startproc
+; %bb.0:
+	sub	sp, sp, #32
+	.cfi_def_cfa_offset 32
+	stp	x29, x30, [sp, #16]             ; 16-byte Folded Spill
+	add	x29, sp, #16
+	.cfi_def_cfa w29, 16
+	.cfi_offset w30, -8
+	.cfi_offset w29, -16
+	stur	wzr, [x29, #-4]
+	mov	w0, #3510
+	bl	_exit
+	.cfi_endproc
+                                        ; -- End function
+.subsections_via_symbols

section_1/funcs/apple-linux-convergence.S

@@ -0,0 +1,156 @@
+/*  Macros to permit the "same" assembly language to build on ARM64
+    Linux systems as well as Apple Silicon systems.
+
+    See the fuller documentation at:
+    https://github.com/pkivolowitz/asm_book/blob/main/macros/README.md
+
+    Perry Kivolowitz
+    A Gentle Introduction to Assembly Language
+*/
+
+.macro  GLD_PTR     xreg, label
+#if defined(__APPLE__)
+        adrp	    \xreg, _\label@GOTPAGE
+        ldr	        \xreg, [\xreg, _\label@GOTPAGEOFF]
+#else
+        ldr         \xreg, =\label
+        ldr         \xreg, [\xreg]
+#endif
+.endm
+
+.macro  GLD_ADDR    xreg, label     // Get a global address
+#if defined(__APPLE__)
+        adrp	    \xreg, _\label@GOTPAGE
+        add         \xreg, \xreg, _\label@GOTPAGEOFF
+#else
+        ldr         \xreg, =\label
+#endif
+.endm
+
+.macro  LLD_ADDR xreg, label
+#if defined(__APPLE__)
+        adrp    \xreg, \label@PAGE
+        add     \xreg, \xreg, \label@PAGEOFF
+#else
+        ldr         \xreg, =\label
+#endif
+.endm
+
+.macro  LLD_DBL xreg, dreg, label
+#if defined(__APPLE__)
+        adrp    \xreg, \label@PAGE
+        add     \xreg, \xreg, \label@PAGEOFF
+        ldur    \dreg, [\xreg]
+//      fmov    \dreg, \xreg
+#else
+        ldr     \xreg, =\label
+        ldur    \dreg, [\xreg]
+#endif
+.endm
+
+.macro  LLD_FLT xreg, sreg, label
+#if defined(__APPLE__)
+        adrp    \xreg, \label@PAGE
+        add     \xreg, \xreg, \label@PAGEOFF
+        ldur    \sreg, [\xreg]
+#else
+        ldr     \xreg, =\label
+        ldur    \sreg, [\xreg]
+#endif
+.endm
+
+.macro GLABEL label
+#if defined(__APPLE__)
+        .global _\label
+#else
+        .global \label
+#endif
+.endm
+
+.macro MAIN
+#if defined(__APPLE__)
+_main:
+#else
+main:
+#endif
+.endm
+
+/*  Fetching the address of the externally defined errno is quite
+    different on Apple and Linux. This macro leaves the address of
+    errno in x0.
+*/
+.macro  ERRNO_ADDR
+#if defined(__APPLE__)
+        bl      ___error
+#else
+        bl      __errno_location
+#endif
+.endm
+
+.macro  CRT label
+#if defined(__APPLE__)
+        bl  _\label
+#else
+        bl  \label
+#endif
+.endm
+
+.macro  START_PROC          // after starting label
+        .cfi_startproc
+.endm
+
+.macro  END_PROC            // after the return
+        .cfi_endproc
+.endm
+
+.macro  PUSH_P  a, b 
+        stp     \a, \b, [sp, -16]!
+.endm
+
+.macro  PUSH_R  a 
+        str     \a, [sp, -16]!
+.endm
+
+.macro  POP_P   a, b 
+        ldp     \a, \b, [sp], 16
+.endm
+
+.macro  POP_R   a 
+        ldr     \a, [sp], 16
+.endm
+
+/*  The smaller of src_a and src_b is put into dest. A cmp instruction
+    or other instruction that sets the flags must be performed first.
+    This macro makes it easy to remember which register does what in the
+    csel.
+    
+    Thank you to u/TNorthover for nudge to add the cmp.
+*/
+
+.macro  MIN     src_a, src_b, dest
+        cmp     \src_a, \src_b
+        csel    \dest, \src_a, \src_b, LT
+.endm
+
+/*  The larger of src_a and src_b is put into dest. A cmp instruction
+    or other instruction that sets the flags must be performed first.
+    This macro makes it easy to remember which register does what in the
+    csel.
+
+    Thank you to u/TNorthover for nudge to add the cmp.
+*/
+
+.macro  MAX     src_a, src_b, dest
+        cmp     \src_a, \src_b
+        csel    \dest, \src_a, \src_b, GT
+.endm
+
+.macro  AASCIZ      label, string
+        .p2align    2
+\label: .asciz      "\string"
+.endm
+
+.macro  MOD         src_a, src_b, dest, scratch
+        sdiv        \scratch, \src_a, \src_b
+        msub        \dest, \scratch, \src_b, \src_a
+.endm

section_1/funcs/direct-syscall.S

@@ -0,0 +1,23 @@
+/*  Linux-only by intention as Apple does not conform the the  ARM Linux
+    system  call conventions.  Here, Apple would use x16 where this code
+    uses x8 and a value of 1 where this code uses 93.
+
+    Both platforms are handled correctly if you use the libcrt.
+
+    Also note that the return from main is limited to 8 bits.  Thus, the
+    value used here (3510) will not yield that value, but 182 instead.
+*/
+
+        .p2align    2
+        .text
+        .global     main
+
+main:
+        stp         x29, x30, [sp, -16]!
+        mov         x0, 3510
+        mov         x8, 93
+        svc         0
+        ldp         x29, x30, [sp], 16
+        ret
+
+        .end