From 55383ce52819e714e735988dea8395e6e4fca7d6 Mon Sep 17 00:00:00 2001
From: Sebastian Rasmussen <sebras@gmail.com>
Date: Sun, 27 Oct 2019 14:24:10 +0100
Subject: [PATCH] Attempt to describe purpose of source code in dsksav.s

---
 src/cmd/dsksav.s | 32 +++++++++++++++++++-------------
 1 file changed, 19 insertions(+), 13 deletions(-)

diff --git a/src/cmd/dsksav.s b/src/cmd/dsksav.s
index 2e79929..1392be4 100644
--- a/src/cmd/dsksav.s
+++ b/src/cmd/dsksav.s
@@ -1,26 +1,32 @@
 " dsksav
 
-   iof
-   hlt
-   dzm track
-   -640
+	" Copies the entire file system (except system image and
+	" swap area) from side 1 of the disk onto same location
+	" on side 0.
+	"
+	" I.e. copies the first 6400 blocks from side 1 to side 0.
+
+   iof			" disable interrupts
+   hlt			" halt the computer!
+   dzm track		" start copying from block address 0
+   -640			" transfer 640 chunks of 10 blocks each
    dac c1
 1:
-   lac track
+   lac track		" read chunk of blocks starting at block "track" on side 1
    jms dskrd1
 
-   lac track
+   lac track		" write chunk of blocks starting at block "track" on side 0
    jms dskwr0
 
-   lac track
+   lac track		" proceed to next chunk (of 10 blocks)
    tad d10
    dac track
-   isz c1
-   jmp 1b
+   isz c1		" increment chunks transferred, if there chunks remaining
+   jmp 1b		" ...loop and transfer the next chunk
 
-   hlt
-   sys exit
+   hlt			" ...otherwise halt the computer!
+   sys exit		" call exit system call
 
-track: 0
-c1: 0
+track: 0		" block address of chunk to transfer
+c1: 0			" number of chunks remaining
 d10: 10