From e1385c925a57702621b29e3d24c293643c2ca8a8 Mon Sep 17 00:00:00 2001
From: cuz <cuz@b7a2c559-68d2-44c3-8de9-860c34a00d81>
Date: Mon, 25 Nov 2002 12:38:38 +0000
Subject: [PATCH] New functions to swap register variables

git-svn-id: svn://svn.cc65.org/cc65/trunk@1629 b7a2c559-68d2-44c3-8de9-860c34a00d81
---
 libsrc/runtime/Makefile   |  3 +++
 libsrc/runtime/regswap.s  | 28 ++++++++++++++++++++++++++++
 libsrc/runtime/regswap1.s | 22 ++++++++++++++++++++++
 libsrc/runtime/regswap2.s | 35 +++++++++++++++++++++++++++++++++++
 4 files changed, 88 insertions(+)
 create mode 100644 libsrc/runtime/regswap.s
 create mode 100644 libsrc/runtime/regswap1.s
 create mode 100644 libsrc/runtime/regswap2.s

diff --git a/libsrc/runtime/Makefile b/libsrc/runtime/Makefile
index ede6e7512..4e0a20bfa 100644
--- a/libsrc/runtime/Makefile
+++ b/libsrc/runtime/Makefile
@@ -159,6 +159,9 @@ OBJS = 	add.o		\
 	pushlysp.o	\
        	pushw.o		\
        	pushwsp.o	\
+        regswap.o       \
+        regswap1.o      \
+        regswap2.o      \
 	return0.o	\
 	return1.o	\
        	rsub.o 		\
diff --git a/libsrc/runtime/regswap.s b/libsrc/runtime/regswap.s
new file mode 100644
index 000000000..28e0441af
--- /dev/null
+++ b/libsrc/runtime/regswap.s
@@ -0,0 +1,28 @@
+;
+; Ullrich von Bassewitz, 25.11.2002
+;
+; CC65 runtime: Swap x bytes of register variable space
+;
+
+   	.export	  	regswap
+	.importzp      	sp, regbank, tmp1
+
+.proc	regswap
+
+        sta     tmp1                    ; Store count
+@L1:    lda     regbank,x               ; Get old value
+        pha                             ; Save it
+        lda     (sp),y                  ; Get stack loc
+        sta     regbank,x               ; Store new value
+        pla
+        sta     (sp),y                  ; Store old value
+        inx
+        iny
+        dec     tmp1
+        bne     @L1
+
+	rts
+
+.endproc
+
+
diff --git a/libsrc/runtime/regswap1.s b/libsrc/runtime/regswap1.s
new file mode 100644
index 000000000..e2410f96d
--- /dev/null
+++ b/libsrc/runtime/regswap1.s
@@ -0,0 +1,22 @@
+;
+; Ullrich von Bassewitz, 25.11.2002
+;
+; CC65 runtime: Swap 1 byte of register variable space
+;
+
+   	.export	  	regswap1
+	.importzp      	sp, regbank
+
+.proc	regswap1
+
+        lda     regbank,x               ; Get old value
+        pha                             ; Save it
+        lda     (sp),y                  ; Get stack loc
+        sta     regbank,x               ; Store new value
+        pla
+        sta     (sp),y                  ; Store old value
+	rts
+
+.endproc
+
+
diff --git a/libsrc/runtime/regswap2.s b/libsrc/runtime/regswap2.s
new file mode 100644
index 000000000..50eb6c2a4
--- /dev/null
+++ b/libsrc/runtime/regswap2.s
@@ -0,0 +1,35 @@
+;
+; Ullrich von Bassewitz, 25.11.2002
+;
+; CC65 runtime: Swap 2 bytes of register variable space
+;
+
+   	.export	  	regswap2
+	.importzp      	sp, regbank
+
+.proc	regswap2
+
+; First byte
+
+        lda     regbank,x               ; Get old value
+        pha                             ; Save it
+        lda     (sp),y                  ; Get stack loc
+        sta     regbank,x               ; Store new value
+        pla
+        sta     (sp),y                  ; Store old value
+
+; Second byte
+
+        iny
+        lda     regbank+1,x             ; Get old value
+        pha                             ; Save it
+        lda     (sp),y                  ; Get stack loc
+        sta     regbank+1,x             ; Store new value
+        pla
+        sta     (sp),y                  ; Store old value
+
+	rts
+
+.endproc
+
+
-- 
2.39.5