diff --git a/libbgi/bgi256/_bgi_hspan_raw.c b/libbgi/bgi256/_bgi_hspan_raw.c
index 1a3ae7e..1770bda 100644
--- a/libbgi/bgi256/_bgi_hspan_raw.c
+++ b/libbgi/bgi256/_bgi_hspan_raw.c
@@ -35,7 +35,7 @@
 
 #include "../_bgi.h"
 
-void _bgi_hspan_raw(int x, int y, int len, uint8_t color) __naked
+void _bgi_hspan_raw(int x, int y, int len, uint8_t color) __naked __preserves_regs(d,e)
 {
     __asm
         .globl __gfx_addr_base
diff --git a/libbgi/bgi256/_bgi_plot_raw.c b/libbgi/bgi256/_bgi_plot_raw.c
index 7b6c4aa..91e5ae6 100644
--- a/libbgi/bgi256/_bgi_plot_raw.c
+++ b/libbgi/bgi256/_bgi_plot_raw.c
@@ -11,7 +11,7 @@
 
 #include "../_bgi.h"
 
-void _bgi_plot_raw(int x, int y, uint8_t color) __naked
+void _bgi_plot_raw(int x, int y, uint8_t color) __naked __preserves_regs(d,e)
 {
     __asm
         .globl __gfx_addr_base
diff --git a/libbgi/bgi256/_bgi_read_raw.c b/libbgi/bgi256/_bgi_read_raw.c
index c9bc33e..6887fcc 100644
--- a/libbgi/bgi256/_bgi_read_raw.c
+++ b/libbgi/bgi256/_bgi_read_raw.c
@@ -11,7 +11,7 @@
 
 #include "../_bgi.h"
 
-uint8_t _bgi_read_raw(int x, int y) __naked
+uint8_t _bgi_read_raw(int x, int y) __naked __preserves_regs(d,e)
 {
     (void)x; (void)y;
     __asm
diff --git a/libbgi/bgi256/_bgi_vspan_raw.c b/libbgi/bgi256/_bgi_vspan_raw.c
index 9e791da..fae5690 100644
--- a/libbgi/bgi256/_bgi_vspan_raw.c
+++ b/libbgi/bgi256/_bgi_vspan_raw.c
@@ -24,7 +24,7 @@
 
 #include "../_bgi.h"
 
-void _bgi_vspan_raw(int x, int y, int len, uint8_t color) __naked
+void _bgi_vspan_raw(int x, int y, int len, uint8_t color) __naked __preserves_regs(d,e)
 {
     __asm
         .globl __gfx_addr_base