This PR is a change to pass the [SA-1 RAM protection test](https://github.com/absindx/SNES-TestRoms/tree/main/SA1RamProtectionTest). --- 242e2fd1a1b373c229818ce0b473bfa5aaf07f63 BW-RAM protection was not implemented to make Kirby's Dream Land 3 work. [Reference: Near's post (nesdev)](https://forums.nesdev.org/viewtopic.php?p=237733#p237733) This commit implements the conditions under which BW-RAM protection works as determined from hardware testing. * BW-RAM Protection will not be reflected unless protection is enabled on both SNES and SA-1. * KDL3 sets `CWEN=0`, but `SWEN=80`. not protected. * `$2228 BWPA` is a register for the SNES CPU, but it also affects the SA-1 protection area. --- 654f5f02cef6e390f63c9da39c970bf07446e2e0 Change the BW-RAM mapping range from $400000-$4FFFFF to $400000-$5FFFFF. [Reference: SA-1 Hardware Behavior - SnesLab](https://sneslab.net/wiki/SA-1_Hardware_Behavior#BW-RAM) --- aa1da58d8bb5db1903b8faec668957eb2b6c414d Initialize the following at SA-1 reset. (change `$2200 CCNT.RESB` 1 to 0) * CPU data bank register * CPU stop flag * IO `$222A CIWP` register NOTE: The timing of when these registers are reset is unknown because they cannot be observed in a stopped SA-1 CPU. I include todo as a reminder that there are many unknown behaviors. I'll delete it if it's not needed. KDL3 restarts the SA-1 CPU several times on the title screen. Before this change, KDL3(JPN: Hoshi no Kirby 3, SHA-1: `5038596a1ec450d8f1d7cc07759737bfd996e87f`) was not restarting properly: ```log SA1 008294 sei A:0000 X:0000 Y:0000 S:01ff D:0000 B:00 nv1BdIzc SA1 008295 clc A:0000 X:0000 Y:0000 S:01ff D:0000 B:00 nv1BdIzc SA1 008296 xce A:0000 X:0000 Y:0000 S:01ff D:0000 B:00 nv1BdIzc # (snip) SA1 0082b1 lda #$ff A:0000 X:0000 Y:0000 S:01ff D:0000 B:00 nvMXdIZC SA1 0082b3 sta $222a [00222a] A:00ff X:0000 Y:0000 S:01ff D:0000 B:00 NvMXdIzC # B:00 ... write to CIWP # (snip) SA1 0082cf pea $4040 [004040] A:3600 X:37ff Y:3800 S:37ff D:3600 B:00 nvmxdIzC SA1 0082d2 plb A:3600 X:37ff Y:3800 S:37fd D:3600 B:00 nvmxdIzC SA1 0082d3 plb A:3600 X:37ff Y:3800 S:37fe D:3600 B:40 nvmxdIzC # (snip) [Omitted: 3303247] # reboot from SNES CPU (CCNT.RESB) SA1 008294 sei A:0000 X:37ff Y:3800 S:37ff D:3600 B:40 nvmxdIZC SA1 008295 clc A:0000 X:37ff Y:3800 S:37ff D:3600 B:40 nvmxdIZC SA1 008296 xce A:0000 X:37ff Y:3800 S:37ff D:3600 B:40 nvmxdIZc SA1 008297 sep #$20 A:0000 X:37ff Y:3800 S:37ff D:3600 B:40 nvmxdIZc # (snip) SA1 0082b1 lda #$ff A:0000 X:37ff Y:3800 S:37ff D:3600 B:40 nvMxdIZc SA1 0082b3 sta $222a [40222a] A:00ff X:37ff Y:3800 S:37ff D:3600 B:40 NvMxdIzc # B:40 ... write to incorrect address ($40222a = BW-RAM) ``` The data bank register `B` has not been reset and an access to a different address is occurring. Although not related to BW-RAM protection, other registers probably need to be reset as well. Further hardware testing is required. --- These commits boot KDL3 with BW-RAM protection implemented.
このコミットが含まれているのは:
absindx
GitHub
コミット
70f361094b
|
|
@ -37,7 +37,8 @@ auto SA1::BWRAM::writeCPU(n24 address, n8 data) -> void {
|
|||
address = sa1.io.sbm * 0x2000 + (address & 0x1fff);
|
||||
}
|
||||
|
||||
if(!sa1.io.swen && (n18)address < 0x100 << sa1.io.bwp) return;
|
||||
//note: BW-RAM protection works only when both SWEN and CWEN are disabled.
|
||||
if(!sa1.io.swen && !sa1.io.cwen && (n18)address < 0x100 << sa1.io.bwp) return;
|
||||
return write(address, data);
|
||||
}
|
||||
|
||||
|
|
@ -53,11 +54,6 @@ auto SA1::BWRAM::readSA1(n24 address, n8 data) -> n8 {
|
|||
}
|
||||
}
|
||||
|
||||
//note: CWEN is not emulated, as it breaks Kirby's Dream Land 3:
|
||||
//* BWPA = 02 (protect 400000-4003ff)
|
||||
//* CWEN = 00 (writes disabled)
|
||||
//KDL3 proceeds to write to 4001ax and 40032x which must succeed.
|
||||
|
||||
auto SA1::BWRAM::writeSA1(n24 address, n8 data) -> void {
|
||||
if(sa1.io.sw46 == 0) {
|
||||
//$40-43:0000-ffff x 32 projection
|
||||
|
|
@ -75,6 +71,15 @@ auto SA1::BWRAM::readLinear(n24 address, n8 data) -> n8 {
|
|||
}
|
||||
|
||||
auto SA1::BWRAM::writeLinear(n24 address, n8 data) -> void {
|
||||
//note: BW-RAM protection works only when both SWEN and CWEN are disabled.
|
||||
//this is required for Kirby's Dream Land 3 to work:
|
||||
//* BWPA = 02 (protect 400000-4003ff)
|
||||
//* SWEN = 80 (writes enabled)
|
||||
//* CWEN = 00 (writes disabled)
|
||||
//KDL3 proceeds to write to 4001ax and 40032x which must succeed.
|
||||
//note: BWPA also affects SA-1 protection
|
||||
if(!sa1.io.swen && !sa1.io.cwen && (n18)address < 0x100 << sa1.io.bwp) return;
|
||||
|
||||
return write(address, data);
|
||||
}
|
||||
|
||||
|
|
|
|||
|
|
@ -101,8 +101,16 @@ auto SA1::writeIOCPU(n24 address, n8 data) -> void {
|
|||
//(CCNT) SA-1 control
|
||||
case 0x2200:
|
||||
if(io.sa1_resb && !data.bit(5)) {
|
||||
//reset SA-1 CPU (PC bank set to 0x00)
|
||||
//reset SA-1 CPU (PC bank and data bank set to 0x00, clear STP status)
|
||||
r.pc.d = io.crv;
|
||||
r.b = 0x00;
|
||||
r.stp = false;
|
||||
//todo: probably needs a SA-1 CPU reset
|
||||
//reset r.s, r.e, r.wai ...
|
||||
|
||||
//reset io status
|
||||
//todo: reset timing is unknown, CIWP is set to 0 at reset
|
||||
io.ciwp = 0x00;
|
||||
}
|
||||
|
||||
io.smeg = data.bit(0,3);
|
||||
|
|
|
|||
|
|
@ -37,7 +37,7 @@ auto SA1::read(n24 address) -> n8 {
|
|||
}
|
||||
|
||||
if((address & 0x40e000) == 0x006000 //00-3f,80-bf:6000-7fff
|
||||
|| (address & 0xf00000) == 0x400000 //40-4f:0000-ffff
|
||||
|| (address & 0xe00000) == 0x400000 //40-5f:0000-ffff
|
||||
|| (address & 0xf00000) == 0x600000 //60-6f:0000-ffff
|
||||
) {
|
||||
step();
|
||||
|
|
@ -81,7 +81,7 @@ auto SA1::write(n24 address, n8 data) -> void {
|
|||
}
|
||||
|
||||
if((address & 0x40e000) == 0x006000 //00-3f,80-bf:6000-7fff
|
||||
|| (address & 0xf00000) == 0x400000 //40-4f:0000-ffff
|
||||
|| (address & 0xe00000) == 0x400000 //40-5f:0000-ffff
|
||||
|| (address & 0xf00000) == 0x600000 //60-6f:0000-ffff
|
||||
) {
|
||||
step();
|
||||
|
|
|
|||
読み込み中…
新しいイシューから参照