diff --git a/libsrc/pce/memcpy.s b/libsrc/pce/memcpy.s
index b06dad645..e3b7bde34 100644
--- a/libsrc/pce/memcpy.s
+++ b/libsrc/pce/memcpy.s
@@ -4,7 +4,7 @@
 ; block-copy instructions.
 ;
 ; 2003-08-20, Ullrich von Bassewitz
-; 2015-10-11, Greg King
+; 2015-11-02, Greg King
 ;
 ; void* __fastcall__ memcpy (void* dest, const void* src, size_t size);
 ;
@@ -16,7 +16,7 @@
         .export         _memcpy
         .export         memcpy_increment, memcpy_transfer, memcpy_getparams
 
-        .import         popax
+        .import         incsp2, popax
         .importzp       sp, ptr1, ptr2, ptr3
 
 
@@ -68,12 +68,23 @@ memcpy_transfer:
 memcpy_getparams:
         sta     ptr3
         stx     ptr3+1                  ; save size
+        ora     ptr3+1
+        bne     @L1
 
-        jsr     popax
+; The size is zero; copy nothing; just return the dest address.
+; (The HuC6280's transfer instructions can't copy $0000 bytes;
+;  they would copy $10000 [64K] bytes instead.)
+
+        ply                             ; drop return address
+        plx
+        jsr     incsp2                  ; drop src address
+        jmp     popax                   ; get pointer; return it as result
+
+@L1:    jsr     popax
         sta     ptr1
         stx     ptr1+1                  ; save src
 
-; (Direct stack access is four cycles faster [total cycle count].)
+; (Direct stack access is six cycles faster [total cycle count].)
 
         ldy     #1                      ; save dest
         lda     (sp),y                  ; get high byte
@@ -85,10 +96,10 @@ memcpy_getparams:
 
 ; ----------------------------------------------------------------------
 ; The transfer instructions use inline arguments.
-; Therefore, we must build the instruction in the DATA segment.
+; Therefore, we must build the instruction, in the DATA segment.
 
 .data
 
 transfer:
         tii     $FFFF, $FFFF, $0001
-        jmp     popax                   ; get pointer; and, return it as result
+        jmp     popax                   ; get pointer; return it as result
diff --git a/testcode/lib/pce/Makefile b/testcode/lib/pce/Makefile
index 1fee199fd..9a4dd7506 100644
--- a/testcode/lib/pce/Makefile
+++ b/testcode/lib/pce/Makefile
@@ -1,3 +1,4 @@
+.PHONY: all clean test
 
 all: conio.pce
 
@@ -5,9 +6,7 @@ conio.pce: conio.c
 	../../../bin/cl65 -t pce conio.c --mapfile conio.map -o conio.pce
 
 clean:
-	$(RM) conio.pce
-	$(RM) conio.map
+	$(RM) conio.o conio.pce conio.map
 
 test: conio.pce
 	mednafen -force_module pce conio.pce
-
diff --git a/testcode/lib/pce/conio.c b/testcode/lib/pce/conio.c
index d22fe58ee..a4bd63b15 100644
--- a/testcode/lib/pce/conio.c
+++ b/testcode/lib/pce/conio.c
@@ -1,4 +1,3 @@
-
 #include <conio.h>
 #include <time.h>
 #include <joystick.h>
@@ -13,7 +12,7 @@ void main(void)
         int i, j;
         clock_t clk;
         char* p;
-        unsigned char xsize, ysize, n;
+        unsigned char xsize, ysize, n, nn;
 
         joy_install(&joy_static_stddrv);
 
@@ -40,11 +39,12 @@ void main(void)
                 gotoxy(0, 16 + i);
                 p = malloc(16);
                 memcpy(p, "0123456789abcdef", 16);
-                cprintf("alloced at: %04p - %c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c", p,
+                cprintf("alloc'ed at: %04p - %c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c", p,
                         p[0],p[1],p[2],p[3],p[4],p[5],p[6],p[7],
                         p[8],p[9],p[10],p[11],p[12],p[13],p[14],p[15]
                 );
         }
+        memcpy(p, main, 0);     /* test that a zero length doesn't copy 64K */
 
         gotoxy(0,ysize - 1);
         for (i = 0; i < xsize; ++i) {
@@ -108,14 +108,22 @@ void main(void)
                 }
 
                 gotoxy(xsize - 10, 3);
-                j = (n >> 5) & 1;
-                revers(j);
-                cputc(j ? 'R' : ' ');
+                nn = (n >> 5) & 1;
+                revers(nn);
+                cputc(nn ? 'R' : ' ');
                 cputs(" revers");
                 revers(0);
 
+                if ((n & 0x1f) == 0x00) {
+                        nn = p[15];
+                        ((char*)memmove(p + 1, p, 15))[-1] = nn;
+                        gotoxy(22, 19);
+                        cprintf("%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c",
+                                p[0],p[1],p[ 2],p[ 3],p[ 4],p[ 5],p[ 6],p[ 7],
+                                p[8],p[9],p[10],p[11],p[12],p[13],p[14],p[15]);
+                }
+
                 waitvblank();
                 ++n;
         }
-        for(;;);
 }