discovered macro names cannot clash with instruction names on gcc linux

more/apple_silicon/apple-linux-convergence.S

@@ -0,0 +1,110 @@
+//  Macros to permit the "same" assembly language to build on ARM64
+//  Linux systems as well as Apple Silicon systems.
+//
+//  Perry Kivolowitz
+//  A Gentle Introduction to Assembly Language
+
+#if defined(__APPLE__)
+
+//  Apple makes a distinction between loading something close by
+//  versus something global. Note the use of GOTPAGE rather then
+//  PAGE. 
+//
+//  Note: this macro dereferences the label getting what is at
+//  the label's address.
+
+.macro  GLD_PTR     xreg, label     // Dereference a global *
+        adrp	    \xreg, _\label@GOTPAGE
+        ldr	        \xreg, [\xreg, _\label@GOTPAGEOFF]
+.endm
+
+.macro  GLD_ADDR    xreg, label     // Get a global address
+        adrp	    \xreg, _\label@GOTPAGE
+        add         \xreg, \xreg, _\label@GOTPAGEOFF
+.endm
+
+//  This macro loads the address of a nearby label.
+
+.macro  LLD_ADDR xreg, label        // Load a local address
+        adrp    \xreg, \label@PAGE
+        add     \xreg, \xreg, \label@PAGEOFF
+.endm
+
+.macro GLABEL label
+        .global _\label
+.endm
+
+.macro MAIN
+_main:
+.endm
+
+.macro  CRT label
+        bl  _\label
+.endm
+
+#else   //  LINUX
+
+.macro GLABEL label
+        .global \label
+.endm
+
+.macro MAIN
+main:
+.endm
+
+.macro  CRT label
+        bl  \label
+.endm
+
+//  This macro treats label as a pointer and dereferences it.
+//  That is, it puts into the xreg what is found at the address
+//  of the label.
+
+.macro  GLD_PTR     xreg, label     // Dereference a global *
+        ldr         \xreg, =\label
+        ldr         \xreg, [\xreg]
+.endm
+
+//  This macro loads the address of a nearby label.
+
+.macro  LLD_ADDR xreg, label
+        ldr         \xreg, =\label
+.endm
+
+
+.macro LD_ADDR xreg, label
+.endm
+
+#endif
+
+.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
+
+.macro  MIN     src_a, src_b, dest
+        csel    \dest, \src_a, \src_b, GT
+.endm
+
+.macro  MAX     src_a, src_b, dest
+        csel    \dest, \src_a, \src_b, LT
+.endm

more/apple_silicon/stub.S

@@ -1,40 +1,45 @@
-#include "macros.S"
+#include "apple-linux-convergence.S"
 
+/*  This is a short demonstration of the macro suite in development
+    to enable writing AARCH64 assembly language once and be able to
+    build on both Apple Silicon and Linux machines.
+
+    Documentation can be found at:
+    https://github.com/pkivolowitz/asm_book
+
+    Perry Kivolowitz
+*/
         .align  2
         .text
         GLABEL main
 
-//  adrp    loads an address using a page number containing the variable
-
-
 MAIN
         START_PROC
-        stp     x21, x30, [sp, -16]!
+        PUSH_P      x21, x30
-        str     x29, [sp, -16]!
+        PUSH_R      x29
-        mov     x29, sp
+        mov         x29, sp
 
-        mov     x0, 8                   // allocating a long
+        mov         x0, 8       // allocating a long's worth of RAM
-        CRT     malloc                  // call malloc()
+        CRT         malloc      // call malloc()
-        mov     x1, 0xFF                // load payload
+        mov         x1, 0xFF    // load payload
-        str     x1, [x0]                // store payload
+        str         x1, [x0]    // store payload
-        LD_ADDR x1, ptr
+        LLD_ADDR    x1, ptr     // local load address
-        str     x0, [x1]
+        str         x0, [x1]
 
-        LD_ADDR x0, fmt     // loads the address of fmt
+        LLD_ADDR    x0, fmt     // loads the address of fmt
-        LD_ADDR x1, ptr     // loads **ptr
+        LLD_ADDR    x1, ptr     // loads **ptr
-        ldr     x1, [x1]    // dereferences **ptr to make *ptr
+        ldr         x1, [x1]    // dereferences **ptr to make *ptr
-        ldr     x2, [x1]    // dereferences *ptr to get value
+        ldr         x2, [x1]    // dereferences *ptr to get value
 #if defined(__APPLE__)
-        stp     x1, x2, [sp, -16]!
+        PUSH_P      x1, x2
-        CRT     printf
+        CRT         printf
-        add     sp, sp, 16
+        add         sp, sp, 16
 #else
-        CRT     printf
+        CRT         printf
 #endif
-        
+        POP_R       x29
-		mov		x0, xzr
+		POP_P	    x21, x30
-        ldr     x29, [sp], 16
+		mov		    x0, xzr
-		ldp		x21, x30, [sp], 16
 		ret
         END_PROC