diff --git a/compiler/res/prog8lib/c64/syslib.p8 b/compiler/res/prog8lib/c64/syslib.p8
index ba58ef10d..cf02611a6 100644
--- a/compiler/res/prog8lib/c64/syslib.p8
+++ b/compiler/res/prog8lib/c64/syslib.p8
@@ -699,6 +699,23 @@ cx16 {
     &uword r14 = $cf1c
     &uword r15 = $cf1e
 
+    &word r0s  = $cf00
+    &word r1s  = $cf02
+    &word r2s  = $cf04
+    &word r3s  = $cf06
+    &word r4s  = $cf08
+    &word r5s  = $cf0a
+    &word r6s  = $cf0c
+    &word r7s  = $cf0e
+    &word r8s  = $cf10
+    &word r9s  = $cf12
+    &word r10s = $cf14
+    &word r11s = $cf16
+    &word r12s = $cf18
+    &word r13s = $cf1a
+    &word r14s = $cf1c
+    &word r15s = $cf1e
+
     &ubyte r0L  = $cf00
     &ubyte r1L  = $cf02
     &ubyte r2L  = $cf04
@@ -732,4 +749,38 @@ cx16 {
     &ubyte r13H = $cf1b
     &ubyte r14H = $cf1d
     &ubyte r15H = $cf1f
+
+    &byte r0sL  = $cf00
+    &byte r1sL  = $cf02
+    &byte r2sL  = $cf04
+    &byte r3sL  = $cf06
+    &byte r4sL  = $cf08
+    &byte r5sL  = $cf0a
+    &byte r6sL  = $cf0c
+    &byte r7sL  = $cf0e
+    &byte r8sL  = $cf10
+    &byte r9sL  = $cf12
+    &byte r10sL = $cf14
+    &byte r11sL = $cf16
+    &byte r12sL = $cf18
+    &byte r13sL = $cf1a
+    &byte r14sL = $cf1c
+    &byte r15sL = $cf1e
+
+    &byte r0sH  = $cf01
+    &byte r1sH  = $cf03
+    &byte r2sH  = $cf05
+    &byte r3sH  = $cf07
+    &byte r4sH  = $cf09
+    &byte r5sH  = $cf0b
+    &byte r6sH  = $cf0d
+    &byte r7sH  = $cf0f
+    &byte r8sH  = $cf11
+    &byte r9sH  = $cf13
+    &byte r10sH = $cf15
+    &byte r11sH = $cf17
+    &byte r12sH = $cf19
+    &byte r13sH = $cf1b
+    &byte r14sH = $cf1d
+    &byte r15sH = $cf1f
 }
diff --git a/compiler/res/prog8lib/cx16/syslib.p8 b/compiler/res/prog8lib/cx16/syslib.p8
index 8fa4ea50b..1d6e60205 100644
--- a/compiler/res/prog8lib/cx16/syslib.p8
+++ b/compiler/res/prog8lib/cx16/syslib.p8
@@ -95,7 +95,7 @@ cx16 {
     &uword  IRQ_VEC         = $FFFE     ; 65c02 interrupt vector, determined by the kernal if banked in
 
 
-; the sixteen virtual 16-bit registers
+; the sixteen virtual 16-bit registers in both normal unsigned mode and signed mode (s)
     &uword r0  = $0002
     &uword r1  = $0004
     &uword r2  = $0006
@@ -113,6 +113,23 @@ cx16 {
     &uword r14 = $001e
     &uword r15 = $0020
 
+    &word r0s  = $0002
+    &word r1s  = $0004
+    &word r2s  = $0006
+    &word r3s  = $0008
+    &word r4s  = $000a
+    &word r5s  = $000c
+    &word r6s  = $000e
+    &word r7s  = $0010
+    &word r8s  = $0012
+    &word r9s  = $0014
+    &word r10s = $0016
+    &word r11s = $0018
+    &word r12s = $001a
+    &word r13s = $001c
+    &word r14s = $001e
+    &word r15s = $0020
+
     &ubyte r0L  = $0002
     &ubyte r1L  = $0004
     &ubyte r2L  = $0006
@@ -147,6 +164,39 @@ cx16 {
     &ubyte r14H = $001f
     &ubyte r15H = $0021
 
+    &byte r0sL  = $0002
+    &byte r1sL  = $0004
+    &byte r2sL  = $0006
+    &byte r3sL  = $0008
+    &byte r4sL  = $000a
+    &byte r5sL  = $000c
+    &byte r6sL  = $000e
+    &byte r7sL  = $0010
+    &byte r8sL  = $0012
+    &byte r9sL  = $0014
+    &byte r10sL = $0016
+    &byte r11sL = $0018
+    &byte r12sL = $001a
+    &byte r13sL = $001c
+    &byte r14sL = $001e
+    &byte r15sL = $0020
+
+    &byte r0sH  = $0003
+    &byte r1sH  = $0005
+    &byte r2sH  = $0007
+    &byte r3sH  = $0009
+    &byte r4sH  = $000b
+    &byte r5sH  = $000d
+    &byte r6sH  = $000f
+    &byte r7sH  = $0011
+    &byte r8sH  = $0013
+    &byte r9sH  = $0015
+    &byte r10sH = $0017
+    &byte r11sH = $0019
+    &byte r12sH = $001b
+    &byte r13sH = $001d
+    &byte r14sH = $001f
+    &byte r15sH = $0021
 
 ; VERA registers
 
diff --git a/docs/source/syntaxreference.rst b/docs/source/syntaxreference.rst
index 8e4292bc9..02ef080de 100644
--- a/docs/source/syntaxreference.rst
+++ b/docs/source/syntaxreference.rst
@@ -609,12 +609,14 @@ flag such as Carry (Pc).
 
 
 .. note::
-    The 'virtual' 16-bit registers from the Commander X16 can also be used as ``R0`` .. ``R15`` .
+    The 'virtual' 16-bit registers from the Commander X16 can also be specified as ``R0`` .. ``R15`` .
     This means you don't have to set them up manually before calling a subroutine that takes
     one or more parameters in those 'registers'. You can just list the arguments directly.
     *This also works on the Commodore-64!*  (however they are not as efficient there because they're not in zeropage)
     In prog8 and assembly code these 'registers' are directly accessible too via
-    ``cx16.r0`` .. ``cx16.r15``  (they're memory mapped uword values)
+    ``cx16.r0`` .. ``cx16.r15``  (these are memory mapped uword values),
+    ``cx16.r0s`` .. ``cx16.r15s``  (these are memory mapped word values),
+    and ``L`` / ``H`` variants are also available to directly access the low and high bytes of these.
 
 
 Expressions
diff --git a/examples/cx16/sincos.p8 b/examples/cx16/sincos.p8
index 5cc3d38c5..30ecfd4a8 100644
--- a/examples/cx16/sincos.p8
+++ b/examples/cx16/sincos.p8
@@ -78,7 +78,7 @@ main {
 
         ; circles with "degrees" from 0 to 255
         for r in 0 to 255 {
-            pixelxw = (sin8(r)/2 + 80) as uword
+            pixelxw = ((sin8(r)/2 as word) + 80) as uword
             pixelyb = (cos8(r)/2 + height/2) as ubyte
             graphics.plot(pixelxw, pixelyb)
         }