This page documents information about Mario Teaches Typing
. Many of the tricks demonstrated here are near impossible in real time and documented for the purposes of creating Tool-assisted Speedruns.
rand.
The generator is
seeded from the current time,
before the title screen,
in the common srand(time(NULL)) pattern.
srand:
0x09f6 55 push bp
0x09f7 8bec mov bp, sp
0x09f9 8b4606 mov ax, word [bp+0x6] ; ax = seed
0x09fc c706363c0000 mov word [0x3c36], 0
0x0a02 a3343c mov word [0x3c34], ax ; x = 0x0000:ax
0x0a05 5d pop bp
0x0a06 cb retf
rand:
0x0a07 8b0e363c mov cx, word [0x3c36]
0x0a0b 8b1e343c mov bx, word [0x3c34] ; cx:bx = x
0x0a0f ba5a01 mov dx, 0x15a
0x0a12 b8354e mov ax, 0x4e35 ; dx:ax = 0x015a4e35
0x0a15 e8a6ff call mul32 ; dx:ax = cx:bx * dx:ax
0x0a18 050100 add ax, 1
0x0a1b 83d200 adc dx, 0 ; dx:ax = dx:ax + 1
0x0a1e 8916363c mov word [0x3c36], dx
0x0a22 a3343c mov word [0x3c34], ax ; x = dx:ax
0x0a25 a1363c mov ax, word [0x3c36]
0x0a28 99 cdq ; dx:ax = dx:ax >> 16
0x0a29 25ff7f and ax, 0x7fff ; ax = ax & 0x7fff
0x0a2c cb retf
rand.
static int x = 1;
void srand(unsigned int seed)
{
x = seed;
}
int rand(void)
{
x = x * 22695477 + 1;
return (x >> 16) & 0x7fff;
}
Borland C++ - Copyright 1991 Borland Intl. appears in the file.