started backporting the eradicate code

[dosdemo] / src / dos / vbe.c

diff --git a/src/dos/vbe.c b/src/dos/vbe.c
index 3ada182..05a5883 100644 (file)
--- a/src/dos/vbe.c
+++ b/src/dos/vbe.c
@@ -29,10 +29,10 @@ static int cur_pitch;
 
 int vbe_info(struct vbe_info *info)
 {
-       int i, num;
        void *lowbuf;
        uint16_t seg, sel;
        uint16_t *modeptr;
+       uint32_t offs;
        struct dpmi_regs regs = {0};
 
        assert(sizeof *info == 512);
@@ -63,7 +63,23 @@ int vbe_info(struct vbe_info *info)
        FIXPTR(info->product);
        FIXPTR(info->revstr);
        FIXPTR(info->modes);
-       FIXPTR(info->accel_modes);
+       /* implementations without the accel capability, will use the space taken
+        * by the accel_modes pointer for other data (probably video modes). We
+        * need to check for the capability before "fixing" this pointer, otherwise
+        * we'll shuffle random data.
+        */
+       if(info->caps & VBE_ACCEL) {
+               FIXPTR(info->accel_modes);
+       }
+
+       /* info->modes should be pointing somewhere at the end of the original
+        * low memory buffer. make it point at the same offset in the info
+        * buffer where we copied everything instead.
+        */
+       offs = (char*)info->modes - (char*)lowbuf;
+       if(offs < sizeof *info) {       /* this should always be true */
+               info->modes = (uint16_t*)((char*)info + offs);
+       }
 
        modeptr = info->modes;
        while(*modeptr != 0xffff) {
@@ -96,7 +112,6 @@ int vbe_num_modes(struct vbe_info *info)
 
 int vbe_mode_info(int mode, struct vbe_mode_info *minf)
 {
-       int i, num;
        void *lowbuf;
        uint16_t seg, sel;
        struct dpmi_regs regs = {0};
@@ -191,6 +206,8 @@ void vbe_print_mode_info(FILE *fp, struct vbe_mode_info *minf)
 
        if(minf->attr & VBE_ATTR_LFB) {
                fprintf(fp, " lfb@%lx", (unsigned long)minf->fb_addr);
+       } else {
+               fprintf(fp, " %xkb/bank", (unsigned int)minf->bank_size);
        }
 
        fprintf(fp, " [");