From owner-svn-src-projects@FreeBSD.ORG  Sun Aug 12 04:50:27 2012
Return-Path: <owner-svn-src-projects@FreeBSD.ORG>
Delivered-To: svn-src-projects@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52])
	by hub.freebsd.org (Postfix) with ESMTP id 38DD2106566B;
	Sun, 12 Aug 2012 04:50:27 +0000 (UTC)
	(envelope-from andrew@FreeBSD.org)
Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c])
	by mx1.freebsd.org (Postfix) with ESMTP id 23E518FC0A;
	Sun, 12 Aug 2012 04:50:27 +0000 (UTC)
Received: from svn.freebsd.org (localhost [127.0.0.1])
	by svn.freebsd.org (8.14.4/8.14.4) with ESMTP id q7C4oQ6M037956;
	Sun, 12 Aug 2012 04:50:26 GMT (envelope-from andrew@svn.freebsd.org)
Received: (from andrew@localhost)
	by svn.freebsd.org (8.14.4/8.14.4/Submit) id q7C4oQMf037954;
	Sun, 12 Aug 2012 04:50:26 GMT (envelope-from andrew@svn.freebsd.org)
Message-Id: <201208120450.q7C4oQMf037954@svn.freebsd.org>
From: Andrew Turner <andrew@FreeBSD.org>
Date: Sun, 12 Aug 2012 04:50:26 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-projects@freebsd.org
X-SVN-Group: projects
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Cc: 
Subject: svn commit: r239208 - projects/arm_eabi/sys/libkern/arm
X-BeenThere: svn-src-projects@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: "SVN commit messages for the src &quot; projects&quot;
	tree" <svn-src-projects.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-projects>, 
	<mailto:svn-src-projects-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-projects>
List-Post: <mailto:svn-src-projects@freebsd.org>
List-Help: <mailto:svn-src-projects-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-projects>, 
	<mailto:svn-src-projects-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sun, 12 Aug 2012 04:50:27 -0000

Author: andrew
Date: Sun Aug 12 04:50:26 2012
New Revision: 239208
URL: http://svn.freebsd.org/changeset/base/239208

Log:
  Document __aeabi_ldivmod and __aeabi_uldivmod. Add a comment of what these
  functions are doing.

Modified:
  projects/arm_eabi/sys/libkern/arm/ldivmod.S

Modified: projects/arm_eabi/sys/libkern/arm/ldivmod.S
==============================================================================
--- projects/arm_eabi/sys/libkern/arm/ldivmod.S	Sun Aug 12 02:51:28 2012	(r239207)
+++ projects/arm_eabi/sys/libkern/arm/ldivmod.S	Sun Aug 12 04:50:26 2012	(r239208)
@@ -28,9 +28,24 @@
 #include <machine/asm.h>
 __FBSDID("$FreeBSD$");
 
+/*
+ * These calculate:
+ * q = n / m 
+ * With a remainer r.
+ *
+ * They take n in {r0, r1} and m in {r2, r3} then pass them into the
+ * helper function. The hepler functions return q in {r0, r1} as
+ * required by the API spec however r is returned on the stack. The
+ * ABI required us to return r in {r2, r3}.
+ *
+ * We need to allocate 8 bytes on the stack to store r, the link
+ * register, and a pointer to the space where the helper function
+ * will write r to. After returning from the helper fuinction we load
+ * the old link register and r from the stack and return.
+ */
 ENTRY_NP(__aeabi_ldivmod)
 	sub	sp, sp, #8	/* Space for the remainder */
-	stmfd	sp!, {sp, lr}	/* Sace the rem pointer and lr */
+	stmfd	sp!, {sp, lr}	/* Save a pointer to the above space and lr */
 	bl	PIC_SYM(_C_LABEL(__kern_ldivmod), PLT)
 	ldr	lr, [sp, #4]	/* Restore lr */
 	add	sp, sp, #8	/* Move sp to the remainder value */
@@ -39,7 +54,7 @@ ENTRY_NP(__aeabi_ldivmod)
 
 ENTRY_NP(__aeabi_uldivmod)
 	sub	sp, sp, #8	/* Space for the remainder */
-	stmfd	sp!, {sp, lr}	/* Sace the rem pointer and lr */
+	stmfd	sp!, {sp, lr}	/* Save a pointer to the above space and lr */
 	bl	PIC_SYM(_C_LABEL(__qdivrem), PLT)
 	ldr	lr, [sp, #4]	/* Restore lr */
 	add	sp, sp, #8	/* Move sp to the remainder value */