METHODDEF void
write_ems_store(j_common_ptr cinfo, backing_store_ptr info, void FAR * buffer_address, long file_offset, long byte_count)
{
EMScontext ctx;
EMSspec spec;
spec.length = byte_count;
SRC_TYPE(spec) = 0;
SRC_HANDLE(spec) = 0;
SRC_PTR(spec) = buffer_address;
DST_TYPE(spec) = 1;
DST_HANDLE(spec) = info->handle.ems_handle;
DST_PAGE(spec) = (unsigned short)(file_offset / EMSPAGESIZE);
DST_OFFSET(spec) = (unsigned short)(file_offset % EMSPAGESIZE);
ctx.ds_si = (void far *)&spec;
ctx.ax = 0x5700; /* move memory region */
jems_calldriver((EMScontext far *) & ctx);
if(HIBYTE(ctx.ax) != 0)
ERREXIT(cinfo, JERR_EMS_WRITE);
}
METHODDEF void
read_ems_store (backing_store_ptr info, void FAR * buffer_address,
long file_offset, long byte_count)
{
EMScontext ctx;
EMSspec spec;
spec.length = byte_count;
SRC_TYPE(spec) = 1;
SRC_HANDLE(spec) = info->handle.ems_handle;
SRC_PAGE(spec) = (unsigned short) (file_offset / EMSPAGESIZE);
SRC_OFFSET(spec) = (unsigned short) (file_offset % EMSPAGESIZE);
DST_TYPE(spec) = 0;
DST_HANDLE(spec) = 0;
DST_PTR(spec) = buffer_address;
ctx.ds_si = (void far *) & spec;
ctx.ax = 0x5700; /* move memory region */
jems_calldriver((EMScontext far *) & ctx);
if (HIBYTE(ctx.ax) != 0)
ERREXIT(methods, "read from expanded memory failed");
}