diff options
| -rw-r--r-- | memdisk/setup.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/memdisk/setup.c b/memdisk/setup.c index 43151898..bf3d5d63 100644 --- a/memdisk/setup.c +++ b/memdisk/setup.c @@ -705,6 +705,39 @@ static int stack_needed(void) return v; } +/* + * Specify max RAM by reservation + * Adds a reservation to data in INT15h to prevent access to the top of RAM + * if there's any above the point specified. + */ +void int15maxres(uint32_t restop) +{ + uint32_t ramtop; + + if (high_mem) { + ramtop = high_mem + (1<<24); + } else if (low_mem) { + ramtop = low_mem + (1<<20); + } else { + ramtop = 0; + } + + /* printf(" TOP RAM-%08x RES-%08x", ramtop, restop); */ + if (restop < ramtop) { + /* printf(" (A)"); */ + insertrange(restop, (ramtop - restop), 3); + parse_mem(); + } + if (high_mem) { + ramtop = high_mem + (1<<24); + } else if (low_mem) { + ramtop = low_mem + (1<<20); + } else { + ramtop = 0; + } + /* printf(" NOW RAM-%08x\n", ramtop); */ +} + struct real_mode_args rm_args; /* @@ -737,6 +770,7 @@ void setup(const struct real_mode_args *rm_args_ptr) int no_bpt; /* No valid BPT presented */ uint32_t boot_seg = 0; /* Meaning 0000:7C00 */ uint32_t boot_len = 512; /* One sector */ + const char *p; /* We need to copy the rm_args into their proper place */ memcpy(&rm_args, rm_args_ptr, sizeof rm_args); @@ -942,6 +976,10 @@ void setup(const struct real_mode_args *rm_args_ptr) pptr->cd_pkt.geom3 = (uint8_t)(pptr->heads); } + if ((p = getcmditem("int15maxres")) != CMD_NOTFOUND) { + int15maxres(atou(p)); + } + /* The size is given by hptr->total_size plus the size of the E820 map -- 12 bytes per range; we may need as many as 2 additional ranges (each insertrange() can worst-case turn 1 area into 3) |