According to DJGPP's docs, we better save ebpHEADmain

1 files changed, 6 insertions, 2 deletions

diff --git a/src/vga.c b/src/vga.c
index fc041d6..12d5928 100644
--- a/src/vga.c
+++ b/src/vga.c
@@ -125,6 +125,7 @@ void ubox_blit_c(const uint8_t *sprite, const ubox_rect *dst, uint8_t c)
     uint8_t *dtarget = target + dst->x + dst->y * 320;
 
     asm volatile (
+        "push %%ebp\n\t"
         "movl $320, %%ebp\n\t"
         "subl %%ecx, %%ebp\n\t"
         "blit_c_w:\n\t"
@@ -146,11 +147,12 @@ void ubox_blit_c(const uint8_t *sprite, const ubox_rect *dst, uint8_t c)
         "addl %%ebp, %%edi\n\t"
         "decl %%ebx\n\t"
         "jne blit_c_w\n\t"
+        "pop %%ebp\n\t"
         : /*no output */
         : "S" (sprite), "D" (dtarget),
         "b" ((uint32_t)dst->h), "d" ((uint32_t)c),
         "c" ((uint32_t)dst->w), "i" (UBOX_TRANSPARENT)
-        : "eax", "ebp"
+        : "eax"
     );
 }
 
@@ -161,6 +163,7 @@ void ubox_blitrc(const uint8_t *sprite, const ubox_rect *src, const ubox_rect *d
     sprite += src->x + src->y * src->w;
 
     asm volatile (
+        "push %%ebp\n\t"
         "movl $320, %%ebp\n\t"
         "subl %%ecx, %%ebp\n\t"
         "blitrc_w:\n\t"
@@ -179,11 +182,12 @@ void ubox_blitrc(const uint8_t *sprite, const ubox_rect *src, const ubox_rect *d
         "addl %%ebp, %%edi\n\t"
         "decl %%ebx\n\t"
         "jne blitrc_w\n\t"
+        "push %%ebp\n\t"
         : /*no output */
         : "S" (sprite), "D" (dtarget),
         "b" ((uint32_t)dst->h), "d" ((uint32_t)(src->w - dst->w)),
         "c" ((uint32_t)dst->w), "i" (UBOX_TRANSPARENT)
-        : "eax", "ebp"
+        : "eax"
     );
 }