From c3e769c44e072faebd5dc87582ff832bc13ee184 Mon Sep 17 00:00:00 2001
From: Marti Bolivar <mbolivar@leaflabs.com>
Date: Mon, 12 Sep 2011 16:10:10 -0400
Subject: common_rom.inc: More comments.

Explain what's going on so unfamiliar readers have more hope.
---
 support/ld/common_rom.inc | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

(limited to 'support')

diff --git a/support/ld/common_rom.inc b/support/ld/common_rom.inc
index 05edf3c..7284492 100644
--- a/support/ld/common_rom.inc
+++ b/support/ld/common_rom.inc
@@ -64,17 +64,20 @@ SECTIONS
         KEEP (*(SORT(.dtors.*)))
         KEEP (*crtend.o(.dtors))
 
+        /*
+         * struct __cs3_region used during __cs3_start_c
+         */
         . = ALIGN(4);
         __cs3_regions = .;
-        LONG (0)
-        LONG (__cs3_region_init_ram)
-        LONG (__cs3_region_start_ram)
-        LONG (__cs3_region_init_size_ram)
-        LONG (__cs3_region_zero_size_ram)
+        LONG (0)                          /* flags */
+        LONG (__cs3_region_init_ram)      /* initial contents */
+        LONG (__cs3_region_start_ram)     /* start address */
+        LONG (__cs3_region_init_size_ram) /* size of initial data */
+        LONG (__cs3_region_zero_size_ram) /* additional size to be zeroed */
       } > REGION_TEXT
 
     /*
-     * .ARM.exidx exception unwinding
+     * .ARM.exidx exception unwinding; mandated by ARM's C++ ABI
      */
     __exidx_start = .;
     .ARM.exidx :
@@ -92,14 +95,16 @@ SECTIONS
         _etext = .;
       } > REGION_TEXT
 
-    /* We allow users to allocate into flash with this section */
+    /*
+     * .USER_FLASH: We allow users to allocate into Flash here
+     */
     .USER_FLASH :
       {
         *(.USER_FLASH)
       } > rom
 
     /*
-     * Start of data
+     * .data
      */
     .data :
       {
@@ -111,6 +116,9 @@ SECTIONS
         _edata = .;
       } > REGION_DATA AT> REGION_TEXT
 
+    /*
+     * .bss
+     */
     .bss :
       {
         *(.bss .bss.* .gnu.linkonce.b.*)
@@ -119,6 +127,10 @@ SECTIONS
         _end = .;
       } > REGION_BSS AT> REGION_TEXT
 
+    /*
+     * Constants needed for the pieces of CS3 we use during
+     * board startup; see libcs3_stm32_src/.
+     */
     __cs3_region_init_ram = LOADADDR (.data);
     __cs3_region_init_size_ram = _edata - ADDR (.data);
     __cs3_region_zero_size_ram = _end - _edata;
-- 
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