renaming and changes to apple macros

README.md

@@ -47,20 +47,27 @@ and how parameters are passed.
 In this book we will use the ARM LINUX conventions. This means:
 
 * You *may* need to run a ARM Linux VM on the Macintosh - even on
-  ARM-based Macs. Why? Apple uses a different calling convention.
+  ARM-based Macs. Why? Apple uses a different calling convention. Keep
+  reading before you get upset.
 
   The convention used in this book should work on all ARM Linux
   machines while the Apple calling convention is specific to Apple
   Silicon-based machines.
 
-  This necessity did not sit well with some on reddit. We listened.
+  This necessity for a VM even when running on an Apple Silicon machine 
+  did not sit well with some on reddit. We listened.
   
   We now have a chapter devoted to bringing Linux and Apple code
-  together to the degree possible. [This chapter](./more/apple_silicon/)
+  together to the degree possible. 
-  also provides a suite of macros that provide this help. If you're
+  
-  willing to adjust how you code (and use the macros), you can
+  [This chapter](./more/apple_silicon/) provides a suite of macros that
-  successfully write assembly language once and build it on both Linux
+  provide this help. If you're willing to adjust how you code (and use
-  and Mac OS.
+  the macros), you can successfully write assembly language once and
+  build it on both Linux and Mac OS.
+
+  The macros are a work in progress. [This
+  link](./macros/apple-linux-convergence.S) will lead to a current copy
+  of them. We will try to keep this file up to date.
 
 * You will need to run WSL (Windows Subsystem for Linux) on ARM-based
   Windows machines. These do exist!
@@ -125,6 +132,10 @@ to only one step in a build sequence. What we talk about as being the
   `#include`. These commands are not part of C or C++. Rather they
   are commands to the preprocessor.
 
+  Note that `gcc` will invoke the C preprocessor only if your assembly
+  language file ends in `.S` - capital S. It may not be invoked if your
+  file ends in a lower case s or any other file extension.
+
 * The *actual* compiler, whose job it is turn high level languages
   such as C and C++ into assembly language.
 
@@ -265,14 +276,14 @@ own section:
 | Chapter | Markdown | PDF |
 | ------- | -------- | --- |
 | 1 | Floating Point | |
-| .... a | [.... What Are Floating Point Numbers?](./section_2/float/what.md) | NA |
+| .... a | [.... What Are Floating Point Numbers?](./section_2/float/what.md) | [Link](./section_2/float/what.pdf) |
-| .... b | [.... Registers (simplified)](./section_2/float/working.md) | NA |
+| .... b | [.... Registers (simplified)](./section_2/float/working.md) | [Link](./section_2/float/working.pdf) |
-| .... c | [.... Literals](./section_2/float/literals.md) | NA |
+| .... c | [.... Literals](./section_2/float/literals.md) | [Link](./section_2/float/literals.pdf) |
 | .... d | [.... `fmov` Not Yet Written](./section_2/float/) | NA |
-| .... e | [.... Conversion To / From Integers](./section_2/float/rounding.md) | NA |
+| .... e | [.... Conversion To / From Integers](./section_2/float/rounding.md) | [Link](./section_2/float/rounding.pdf) |
 | .... f | [.... Four Basic Operations Not Yet Written](./section_2/float/) | NA |
 | .... g | [.... Selected Additional Operations Not Yet Written](./section_2/float/) | NA |
-| .... z | [.... Half Precision Floats](./section_2/float/half.md) | NA |
+| .... z | [.... Half Precision Floats](./section_2/float/half.md) | [Link](./section_2/float/half.pdf) |
 
 ## Section 3 - Bit Manipulation
 

macros/README.md

@@ -0,0 +1 @@
+

macros/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/macros.S

@@ -1,52 +0,0 @@
-//  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__)
-
-.macro LD_ADDR xreg, label 
-        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
-
-.macro GLABEL label
-        .global \label
-.endm
-
-.macro MAIN
-main:
-.endm
-
-.macro  CRT label
-        bl  \label
-.endm
-
-.macro LD_ADDR xreg, label
-        ldr     \xreg, =\label
-.endm
-
-#endif
-
-.macro  START_PROC
-        .cfi_startproc
-.endm
-
-.macro  END_PROC
-        .cfi_endproc
-.endm