public static Ram GetLayoutAnnotated()
{
var ram = new Ram();
// I think this is map layout (when to read a block of sea or something or when to read map data)
// see debug log: trying to find water 02
// code start: c04923
// code end: c04a43
// code never hits: c049b3 (does hit when loading cave map)
// $ed8a00 - $ed9be2
var layoutSource = Rom.ByteArray(0xed8a00);
var output = ram.WordArray(0x7f0000);
var outputf3c6 = ram.ByteArray(0x7ff3c6);
//c04923 php
//c04924 %setAXYto16bit()
//c04926 pha
//c04927 phx
//c04928 phy
//c04929 sta $1c
//c0492b stx $20
//c0492d stz $18
//c0492f stz $1a
//c04931 lda #$03be
//c04934 sta $1e
//c04936 stz $22
//c04938 ldx #$0000
//c0493b stz $f3c6,x
//c0493e inx
//c0493f inx
//c04940 cpx #$0400
//c04943 bcc $493b
//c04945 ldy #$0000
//c04948 tya
//c04949 %setAto8bit()
// c04929
ushort x18x19 = 0;
int x1c = 0x1000; // comes from outside (A)
int x1e = 0x03BE;
byte x1a = 0;
byte x1b = 0;
int x20 = 0; // comes from outside (X)
byte x22 = 0;
// don't have initial values?
byte x24 = 0;
byte x25 = 0;
// $c04945
var y = 0;
// A => 8bit
// .Branch_c0494b -- top
while (true)
{
//c0494b lsr $19
//c0494d ror $18
x18x19 = (ushort)(x18x19 >> 1);
//c0494f lda $19
//c04951 lsr
//c04952 bcs .Branch_c0495b
if ((x18x19 & 0x0100) == 0)
{
//c04954 lda [$00],y
//c04956 iny
//c04957 sta $18
//c04959 dec $19
x18x19 = (ushort)((x18x19 - 0x0100 & 0xff00) + layoutSource[y]);
y++;
}
//.Branch_c0495b
//c0495b lda $18
//c0495d lsr
//c0495e bcc .Branch_c049b4
if ((x18x19 & 0x0001) != 0)
{
//c04960 lda $22
//c04962 lsr
//c04963 bcs .Branch_c0497e
if ((x22 & 0x01) == 0)
{
//c04965 lda [$00],y
//c04967 iny
//c04968 sta $24
//c0496a ldx $1e
//c0496c sta $f3c6,x
x24 = layoutSource[y];
outputf3c6[x1e] = layoutSource[y];
y++;
//c0496f inc $1e
//c04971 bne .Branch_c0497a
//c04973 lda $1f
//c04975 inc
//c04976 and #$03
//c04978 sta $1f
//.Branch_c0497a
x1e++;
x1e &= 0x03ff;
//c0497a inc $22
x22++;
//c0497c bra .Branch_c0494b // back to top
continue;
}
//.Branch_c0497e
//c0497e lda [$00],y
//c04980 iny
//c04981 sta $25
//c04983 ldx $1e
//c04985 sta $f3c6,x
x25 = layoutSource[y];
outputf3c6[x1e] = layoutSource[y];
y++;
//c04988 inc $1e
//c0498a bne .Branch_c04993
//c0498c lda $1f
//c0498e inc
//c0498f and #$03
//c04991 sta $1f
//.Branch_c04993
//c04993 inc $22
x1e++;
x1e &= 0x03ff;
x22++;
//c04995 rep #$20
// ---------------------------------A => 16bit
//c04997 ldx $20
//c04999 lda $24
//c0499b sta $0000,x
//c0499e inx
//c0499f inx
//c049a0 stx $20
output[x20] = (ushort)(x24 + (x25 << 8));
x20 += 2;
//c049a2 dec $1c
x1c--;
//c049a4 beq .Branch_c049ad
if (x1c != 0)
{
//c049a6 lda #$0000
//c049a9 sep #$20
// ---------------------------------A => 8bit
//c049ab bra .Branch_c0494b // back to top
continue;
}
else
{
//.Branch_c049ad
//c049ad %setAXYto16bit()
//c049af ply
//c049b0 plx
//c049b1 pla
//c049b2 plp
//c049b3 rtl
return(ram); // EXIT
}
}
//.Branch_c049b4 // carry will be clear
//c049b4 lda [$00],y
//c049b6 iny
//c049b7 sta $1a
x1a = layoutSource[y];
y++;
//c049b9 lda [$00],y
//c049bb rol
//c049bc rol
//c049bd rol
//c049be and #$03
//c049c0 sta $1b
x1b = (byte)(layoutSource[y] >> 6 & 0x03);
//c049c2 lda [$00],y
//c049c4 iny
//c049c5 and #$3f
//c049c7 clc
//c049c8 adc #$03
//c049ca phy
//c049cb tay
byte counter = (byte)((layoutSource[y] & 0x3f) + 3);
y++;
//.Branch_c049cc
while (true)
{
//c049cc dey
counter--;
//c049cd bmi .Branch_c04a3a
if (SNES.IsNegative16(counter))
{
break;
}
//c049cf lda $22
//c049d1 lsr
//c049d2 bcs .Branch_c049fc
if ((x22 & 0x01) == 0)
{
//c049d4 ldx $1a
//c049d6 lda $f3c6,x
//c049d9 sta $24
//c049db inc $1a
x24 = outputf3c6[x1a]; // TODO: Wrong, needs to be 16bit x1a
x1a++;
//c049dd bne .Branch_c049e8
if (x1a == 0)
{
//c049df lda $1b
//c049e1 inc
//c049e2 and #$03
//c049e4 sta $1b
x1b++;
x1b &= 0x03;
//c049e6 lda $24
}
//.Branch_c049e8
//c049e8 ldx $1e
//c049ea sta $f3c6,x
outputf3c6[x1e] = x24;
//c049ed inc $1e
//c049ef bne .Branch_c049f8
//c049f1 lda $1f
//c049f3 inc
//c049f4 and #$03
//c049f6 sta $1f
//.Branch_c049f8
x1e++;
x1e &= 0x03ff;
//c049f8 inc $22
x22++;
//c049fa bra .Branch_c049cc
}
else
{
//.Branch_c049fc
//c049fc ldx $1a
//c049fe lda $f3c6,x
//c04a01 sta $25
x25 = outputf3c6[x1a]; // TODO: Wrong, needs to be 16bit x1a
//c04a03 inc $1a
x1a++;
//c04a05 bne .Branch_c04a10
if (x1a == 0)
{
//c04a07 lda $1b
//c04a09 inc
//c04a0a and #$03
//c04a0c sta $1b
x1b++;
x1b &= 0x03;
//c04a0e lda $25
}
//.Branch_c04a10
//c04a10 ldx $1e
//c04a12 sta $f3c6,x
outputf3c6[x1e] = x25;
//c04a15 inc $1e
//c04a17 bne .Branch_c04a20
//c04a19 lda $1f
//c04a1b inc
//c04a1c and #$03
//c04a1e sta $1f
//.Branch_c04a20
x1e++;
x1e &= 0x03ff;
//c04a20 inc $22
x22++;
//c04a22 rep #$20
//---------------------------------- A=> 16bit
//c04a24 ldx $20
//c04a26 lda $24
//c04a28 sta $0000,x
//c04a2b inx
//c04a2c inx
//c04a2d stx $20
output[x20] = (ushort)(x24 + (x25 << 8));
x20 += 2;
//c04a2f dec $1c
x1c--;
//c04a31 beq .Branch_c04a3e
if (x1c == 0)
{
return(ram); // EXIT
}
//c04a33 lda #$0000
//c04a36 sep #$20
// ---------------------------------A => 8bit
//c04a38 bra .Branch_c049cc
}
}
//.Branch_c04a3a
//c04a3a ply
//c04a3b jmp Jump_c0494b // back to top
} // end of while
//.Branch_c04a3e -- EXIT
//c04a3e ply
//c04a3f ply
//c04a40 plx
//c04a41 pla
//c04a42 plp
//c04a43 rtl
}
/*
* Work area is ring buffer of $400 bytes, starts as zeros, destination starts at $3be
* Reads from source data in order, writes to output and ring buffer in order
* Command byte is 8 command bits:
* 1 => read one byte (and write to output and ring buffer)
* 0 => read two bytes
* 10 bits are start address in ring buffer
* 6 bits are number of bytes to copy (plus 3, so counter can be 3 to 66)
* copy bytes from ring buffer starting at source address,
* while writing to ring buffer destination address and output at same time)
* So each command byte is followed by 8 to 16 bytes of data
*
*/
// Output is ram $7f0000 - $7f1fff ($2000 bytes)
// A => exitCounter
// X => destinationAddress
public static RamWordArray GetLayout()
{
// TODO: this can be greater simplified and won't require Ram class usage
//(int A, int X) {
// I think this is map layout (when to read a block of sea or something or when to read map data)
// see debug log: trying to find water 02
// code start: c04923
// code end: c04a43
// code never hits: c049b3 (does hit when loading cave map)
// $ed8a00 - $ed9be2
var ram = new Ram();
var layoutSource = Rom.ByteArray(0xed8a00);
var output = ram.WordArray(0x7f0000);
var work = ram.ByteArray(0x7ff3c6);
/*
* Output at $7f0000 should be $2000 bytes
* Each word represents 4 columns by 4 rows of tilemap data --- this might not be right
* So 256 x 256 is reduced to pointers for 64 x 64
* This allows for easy repeat/reuse of blocks of sea etc.
*/
// $18-$19, initialized to 0
// TODO: should resplit these
// $19 is $00 (-1 so $ff, read $18 from source)
// $ff, $7f, $3f, $1f, $0f, $07, $03, $01, $00 = restart
// basically a counter to 8
// regex @"ROR \$18 \[000018\] = \$.{62}C" shows all but first >> puts a 1 in $18 high bit (carry set because bit from $19 is 1)
ushort command = 0;
// $1c -- 16bit -- comes from outside (A)
// each decrement is 2 bytes of output, so $2000 bytes
// TODO: could be replaced with destination address offset? might be more than one setup (dest might not be zero in caves or something)
int exitCounter = 0x1000;
// $1e -- 16bit
// masked with 0x03ff so $400 bytes of ring memory
int workDestination = 0x03be;
// $1a -- 16bit
// masked with 0x03ff so $400 bytes of ring memory
int workSource;
// $20 -- 16bit -- comes from outside (X)
// $0000 to $1ffe by +=2 ($2000 bytes)
int destinationAddress = 0;
// $22 -- 8bit
// overflows from $ff to $00
// is really just high byte/low byte indicator
byte columnIndex = 0;
// don't need initial values
// don't need to be differentiated, could just write byte by byte
// $24
byte lowValue = 0;
// $25
byte highValue = 0;
// Y -- 16bit
var sourceAddress = 0;
while (true)
{
// decrement $19 basically, and rotate a one into the high bit of $18 (except first time in which $18 is thrown out anyways)
command = (ushort)(command >> 1);
// is $19 zero (happens at beginning of every cycle of 8)
// Gets new command byte $18 (each bit says how next bytes are interpreted)
if ((command & 0x0100) == 0)
{
//set $19 to $ff and read $18 from source
command = (ushort)((command - 0x0100 & 0xff00) + layoutSource[sourceAddress]);
sourceAddress++;
}
// is $18 odd (bit 0 == 1) --- command bit is 1
if ((command & 0x0001) != 0)
{
// loads one byte directly
if ((columnIndex & 0x01) == 0)
{
// load low byte direct
lowValue = layoutSource[sourceAddress];
work[workDestination] = layoutSource[sourceAddress];
sourceAddress++;
workDestination++;
workDestination &= 0x03ff;
columnIndex++;
}
else
{
// load high byte direct and write output
highValue = layoutSource[sourceAddress];
work[workDestination] = layoutSource[sourceAddress];
sourceAddress++;
workDestination++;
workDestination &= 0x03ff;
columnIndex++;
output[destinationAddress] = (ushort)(lowValue + (highValue << 8));
destinationAddress += 2;
exitCounter--;
if (exitCounter == 0)
{
return(output); // EXIT
}
}
}
else
{
// is $18 even (bit 0 == 0) --- command bit is 0
// copy part of work into output
// next two source bytes are source address and number of bytes to copy
// destination work buffer continues to fill
// 10 bit number: low byte = ls[sa], high byte lower 2 bits = ls[sa+1] highest 2 bits
// source address is absolute in buffer, not relative
workSource = layoutSource[sourceAddress] + (layoutSource[sourceAddress + 1] << 2 & 0x0300);
// counter is lower 6 bits + 3
// smallest value is (0 + 3) copy 3 bytes
int counter = (layoutSource[sourceAddress + 1] & 0x3f) + 3;
sourceAddress += 2;
while (counter > 0)
{
counter--;
if ((columnIndex & 0x01) == 0)
{
// copy low byte from work buffer
lowValue = work[workSource];
work[workDestination] = lowValue;
workSource++;
workSource &= 0x03ff;
workDestination++;
workDestination &= 0x03ff;
columnIndex++;
}
else
{
// copy high byte from work buffer and write to output
highValue = work[workSource];
work[workDestination] = highValue;
workSource++;
workSource &= 0x03ff;
workDestination++;
workDestination &= 0x03ff;
columnIndex++;
var val = (ushort)(lowValue + (highValue << 8));
output[destinationAddress] = val;
destinationAddress += 2;
exitCounter--;
if (exitCounter == 0)
{
return(output); // EXIT
}
}
}
}
}
}