diff --git a/doc/apple2.sgml b/doc/apple2.sgml
index f1603c4286..bbc3299289 100644
--- a/doc/apple2.sgml
+++ b/doc/apple2.sgml
@@ -334,6 +334,8 @@ usage.
 <item>rebootafterexit
 <item>ser_apple2_slot
 <item>tgi_apple2_mix
+<item>apple2_slowdown
+<item>apple2_speedup
 </itemize>
 
 
diff --git a/doc/funcref.sgml b/doc/funcref.sgml
index c8a8182952..867d579301 100644
--- a/doc/funcref.sgml
+++ b/doc/funcref.sgml
@@ -92,6 +92,8 @@ function.
 
 <itemize>
 <item>_dos_type
+<item><ref id="apple2_slowdown" name="apple2_slowdown">
+<item><ref id="apple2_speedup" name="apple2_speedup">
 <item><ref id="get_ostype" name="get_ostype">
 <item><ref id="gmtime_dt" name="gmtime_dt">
 <item><ref id="mktime_dt" name="mktime_dt">
@@ -103,7 +105,11 @@ function.
 
 <itemize>
 <item>_dos_type
+<item><ref id="apple2_slowdown" name="apple2_slowdown">
+<item><ref id="apple2_speedup" name="apple2_speedup">
 <item><ref id="get_ostype" name="get_ostype">
+<item><ref id="gmtime_dt" name="gmtime_dt">
+<item><ref id="mktime_dt" name="mktime_dt">
 <item>rebootafterexit
 <item><ref id="videomode" name="videomode">
 </itemize>
@@ -1470,6 +1476,40 @@ used in presence of a prototype.
 </quote>
 
 
+<sect1>apple2_slowdown<label id="apple2_slowdown"><p>
+
+<quote>
+<descrip>
+<tag/Function/Forces the Apple IIgs CPU to 1MHz
+<tag/Header/<tt/<ref id="apple2.h" name="apple2.h">/
+<tag/Declaration/<tt/void __fastcall__ apple2_slowdown (void);/
+<tag/Description/The <tt/apple2_slowdown/ function toggles the Apple IIgs CPU
+to 1MHz.
+<tag/Notes/<itemize>
+<item>This function is only available on Apple II.
+</itemize>
+<tag/Availability/cc65
+</descrip>
+</quote>
+
+
+<sect1>apple2_speedup<label id="apple2_speedup"><p>
+
+<quote>
+<descrip>
+<tag/Function/Sets the Apple IIgs CPU to the user preferred speed
+<tag/Header/<tt/<ref id="apple2.h" name="apple2.h">/
+<tag/Declaration/<tt/void __fastcall__ apple2_speedup (void);/
+<tag/Description/The <tt/apple2_speedup/ function toggles the Apple IIgs CPU
+back to the speed set in the IIgs control panel.
+<tag/Notes/<itemize>
+<item>This function is only available on Apple II.
+</itemize>
+<tag/Availability/cc65
+</descrip>
+</quote>
+
+
 <sect1>assert<label id="assert"><p>
 
 <quote>
diff --git a/libsrc/apple2/cpuspeed.s b/libsrc/apple2/cpuspeed.s
new file mode 100644
index 0000000000..00c13fd1e2
--- /dev/null
+++ b/libsrc/apple2/cpuspeed.s
@@ -0,0 +1,33 @@
+;
+; Colin Leroy-Mira <colin@colino.net>, 2024
+;
+; void __fastcall__ apple2_slowdown(void)
+; void __fastcall__ apple2_speedup(void)
+;
+
+        .export         _apple2_slowdown
+        .export         _apple2_speedup
+        .import         apple2_ostype
+
+        .include        "apple2.inc"
+
+_apple2_slowdown:
+        bit     apple2_ostype
+        bpl     :+
+        lda     CYAREG
+        sta     cyareg_orig
+        and     #%01111111
+        sta     CYAREG
+:       rts
+
+_apple2_speedup:
+        bit     apple2_ostype
+        bpl     :+
+        lda     cyareg_orig
+        sta     CYAREG
+:       rts
+
+        .bss
+
+cyareg_orig:
+        .res 1
diff --git a/libsrc/apple2/get_ostype.s b/libsrc/apple2/get_ostype.s
index a1b1eb5bef..cdd3474ef8 100644
--- a/libsrc/apple2/get_ostype.s
+++ b/libsrc/apple2/get_ostype.s
@@ -5,7 +5,7 @@
 ;
 
         .constructor    initostype, 9
-        .export         _get_ostype
+        .export         _get_ostype, apple2_ostype
 
 ; Identify machine according to:
 ; Apple II Miscellaneous TechNote #7, Apple II Family Identification
@@ -18,7 +18,7 @@ initostype:
         bcs     nogs
         tya
         ora     #$80
-done:   sta     ostype
+done:   sta     apple2_ostype
         rts
 nogs:   ldx     #$FF
 next:   inx
@@ -61,10 +61,11 @@ value:  .byte   $38, $10           ; Apple ][
         .code
 
 _get_ostype:
-        lda     ostype
+        lda     apple2_ostype
         ldx     #$00
         rts
 
         .segment        "INIT"
 
-ostype: .res    1
+apple2_ostype:
+        .res    1
diff --git a/libsrc/apple2/sleep.s b/libsrc/apple2/sleep.s
new file mode 100644
index 0000000000..ac2618d400
--- /dev/null
+++ b/libsrc/apple2/sleep.s
@@ -0,0 +1,38 @@
+;
+; Colin Leroy-Mira <colin@colino.net>, 2024
+;
+; void __fastcall__ sleep(unsigned s)
+;
+;
+
+        .export         _sleep
+        .import         _apple2_slowdown
+        .import         _apple2_speedup
+        .importzp       tmp1
+
+MONWAIT         := $FCA8
+
+_sleep:
+        stx     tmp1
+        tay
+        ora     tmp1
+        beq     out
+        jsr     _apple2_slowdown; Down to 1MHz for consistency around MONWAIT
+        bit     $C082
+sleep_1s:
+        ldx     #10             ; Loop 10 times
+:       lda     #200            ; About 100ms
+        jsr     MONWAIT
+        dex
+        bne     :-
+        dey
+        bne     sleep_1s
+        dec     tmp1
+        bmi     done
+        ldy     #$FF
+        bne     sleep_1s
+done:
+        bit     $C080
+        jsr     _apple2_speedup
+out:
+        rts
diff --git a/libsrc/apple2/waitvsync.s b/libsrc/apple2/waitvsync.s
index a4ab5ebb37..60cf134856 100644
--- a/libsrc/apple2/waitvsync.s
+++ b/libsrc/apple2/waitvsync.s
@@ -5,23 +5,15 @@
 ;
         .ifdef  __APPLE2ENH__
 
-        .constructor    initvsync
         .export         _waitvsync
-        .import         _get_ostype
+        .import         apple2_ostype
 
         .include        "apple2.inc"
 
-        .segment        "ONCE"
-
-initvsync:
-        jsr     _get_ostype
-        sta     ostype
-        rts
-
         .code
 
 _waitvsync:
-        bit     ostype
+        bit     apple2_ostype
         bmi     iigs            ; $8x
         bvs     iic             ; $4x
 
@@ -53,8 +45,4 @@ iic:    sei
         cli
         rts
 
-        .segment        "INIT"
-
-ostype: .res    1
-
         .endif                  ; __APPLE2ENH__