Search found 171 matches
- Mon Feb 08, 2021 4:31 pm
- Forum: Programming Discussion
- Topic: Some questions about SH4 asm instruction
- Replies: 7
- Views: 1359
Re: Some questions about SH4 asm instruction
Perfect :) Updating pseudo code : bool IsDivisibleByTwo(ushort value); bool IsDivisibleByFour(ushort value); enum OperandSize {Byte, Word, Long} bool DisplacementTheoreticalCheckFunction(OperandSize size, ushort displacementWanted) { switch(size) { case OperandSize.Byte : return displacementWanted <...
- Mon Feb 08, 2021 2:00 pm
- Forum: Programming Discussion
- Topic: Some questions about SH4 asm instruction
- Replies: 7
- Views: 1359
Re: Some questions about SH4 asm instruction
Do you mean that long values should be divisible by four ?Long values must be aligned to a 4 byte boundary, not just on an even address.
- Mon Feb 08, 2021 1:45 pm
- Forum: Hardware Modification and Repair
- Topic: Laser transplant
- Replies: 1
- Views: 2054
Re: Laser transplant
Hi,
I am not a specialist and I have never done it.
But if you are going to replace the lens bloc why not buy a new one ?
I think there are only two kind of blocks for DC : SPU3200 (yamaha) and SOH-R48 (Samsung).
It depends on GD-Rom drive model.
Hope it helps
I am not a specialist and I have never done it.
But if you are going to replace the lens bloc why not buy a new one ?
I think there are only two kind of blocks for DC : SPU3200 (yamaha) and SOH-R48 (Samsung).
It depends on GD-Rom drive model.
Hope it helps
- Mon Feb 08, 2021 1:24 pm
- Forum: Programming Discussion
- Topic: Some questions about SH4 asm instruction
- Replies: 7
- Views: 1359
Re: Some questions about SH4 asm instruction
Hi, Thanks for your answer. I understand better. The value of the displacement that we give in the instruction for the parameter dsp is what we actually want to do as the displacement (724). The compiler is therefore responsible for internally finding the right value to encode in the 8-bit instructi...
- Sun Feb 07, 2021 3:00 pm
- Forum: Programming Discussion
- Topic: Some questions about SH4 asm instruction
- Replies: 7
- Views: 1359
Some questions about SH4 asm instruction
Hi everybody, I hope you're all safe and in good condition :) I have a question about MOVe global data instructions group : MOV.B @(disp,GBR),R0 MOV.W @(disp,GBR), R0 MOV.L @(disp,GBR),R0 MOV.B R0,@(disp,GBR) MOV.W R0,@(disp,GBR) MOV.L R0,@(disp,GBR) I do not understand what the disp value could be ...
- Thu Apr 19, 2018 2:41 pm
- Forum: Official Reicast Discussion Forum
- Topic: How make a CDI runnable on Reicast ?
- Replies: 3
- Views: 2400
Re: How make a CDI runnable on Reicast ?
Sorry for late answer ... tons of work to do
Well thanks for the script !
It does not solve the problem but it's certainly something on my code ...
The best thing to do is mock some things
Well thanks for the script !
It does not solve the problem but it's certainly something on my code ...
The best thing to do is mock some things
A little framework very little thing ...What are you deving on?
- Sun Jan 28, 2018 4:04 am
- Forum: Official Reicast Discussion Forum
- Topic: How make a CDI runnable on Reicast ?
- Replies: 3
- Views: 2400
How make a CDI runnable on Reicast ?
Hi everybody, I make some code using KOS and want to test it on Reicast. I use common self boot tool like bootBreams and obtain a regular CDI file. But the file do not run on Reicast : it froze after the logo screen. The CDI produced is good and boot up on machine. I noticed that using Reicast some ...
- Wed Sep 27, 2017 11:50 am
- Forum: Programming Discussion
- Topic: Writing some values in memory using assembly
- Replies: 2
- Views: 830
Re: Writing some values in memory using assembly
Well, replacing 0x8C0102B4 by 0xAC0102B4 in my code solves the issue. Dumping either from 0x8C0102B4 or 0xAC0102B4 locations gave the same consistent result. It is certainly, like you said, a data cache issue linked to the unknown behavior of serial upload tool about managing that. Thanks again :)
- Sun Sep 24, 2017 9:37 am
- Forum: Programming Discussion
- Topic: Writing some values in memory using assembly
- Replies: 2
- Views: 830
Writing some values in memory using assembly
Hello everybody, I tried last week a code to compute some things and write result values sequentially using a loop to a field of bytes in main memory at a certain start address. At the very beginning the field of bytes is full of garbage values. After the code was uploaded via serial cable to Dreamc...
- Sat Aug 19, 2017 6:07 pm
- Forum: Programming Discussion
- Topic: About floating point numbers and division instruction
- Replies: 4
- Views: 1169
Re: About floating point numbers and division instruction
I would only add that floatundisf is a part of glibc.
All is said about this topic
Thanks.
All is said about this topic
Thanks.
- Mon Aug 14, 2017 3:57 pm
- Forum: Programming Discussion
- Topic: About floating point numbers and division instruction
- Replies: 4
- Views: 1169
Re: About floating point numbers and division instruction
Ok: thanks for reply :) First to load directly a constant floating point value like PI in a floating point register, the floating point value must be converted in the "IEEE754 Single precision 32-bit format" . There are some online converters and source code to do this. Then, simply hard c...
- Fri Aug 11, 2017 4:07 pm
- Forum: Programming Discussion
- Topic: About floating point numbers and division instruction
- Replies: 4
- Views: 1169
About floating point numbers and division instruction
Hi, I try to understand how division operations can be made on SH4. As I compile in "single mode", it will be float divisions not double. First, I try to de-compile some C code making division with different type of data. But assembly code is quite difficult to understand (even using 01 di...
- Wed Aug 02, 2017 6:10 pm
- Forum: Programming Discussion
- Topic: Equivalent to RTSC x86 indtruction on SH4
- Replies: 6
- Views: 1240
Re: Equivalent to RTSC x86 indtruction on SH4
Thanks you very much, I will see this more closely.
I am every time amazed the number of things undocumented ...
I am every time amazed the number of things undocumented ...
- Mon Jul 31, 2017 9:04 am
- Forum: Programming Discussion
- Topic: Equivalent to RTSC x86 indtruction on SH4
- Replies: 6
- Views: 1240
Equivalent to RTSC x86 indtruction on SH4
Hi, On all X86 architecture, the Time Stamp Counter (TSC) is a 64-bit register counts the number of cycles since reset. It is used as a precise timer (a clock cycle delta). https://en.wikipedia.org/wiki/Time_Stamp_Counter Is there something that could be equivalent on SH4 architecture ? I need a tim...
- Wed Jul 12, 2017 8:10 pm
- Forum: Programming Discussion
- Topic: About GD Rom Drive reading a CD Rom
- Replies: 10
- Views: 2170
Re: About GD Rom Drive reading a CD Rom
Well, I ask about a reading scenario sector with a specific number on a bootable DC disc (a two or more session disc) using KOS sector read function. First is the sector number a relative or absolute addressing number ? For example, if I ask for sector 14598, is it the 14599 th sector of the entire ...
- Sun Jun 25, 2017 5:26 pm
- Forum: Programming Discussion
- Topic: About swapping disc / DC load serial
- Replies: 2
- Views: 627
Re: About swapping disc / DC load serial
I re burn my DC Load Serial disk and now it's fine !
Thanks
Thanks
- Sun Jun 25, 2017 5:22 pm
- Forum: Programming Discussion
- Topic: About GD Rom Drive reading a CD Rom
- Replies: 10
- Views: 2170
Re: About GD Rom Drive reading a CD Rom
Using CD ROM sector read function in KOS, is it possible to read all sector on the CD Rom ?
I try to read sector 0 to test but the function return me an error type SYSTEM ERROR (3).
Thanks for help
I try to read sector 0 to test but the function return me an error type SYSTEM ERROR (3).
Thanks for help
- Fri Jun 23, 2017 6:30 pm
- Forum: Programming Discussion
- Topic: About swapping disc / DC load serial
- Replies: 2
- Views: 627
About swapping disc / DC load serial
Hi everybody, I have a little annoying thing : I use a CD ROM disc on my Dreamcast to boot with DC TOOL Serial. Then, sometimes, I need to change the disc (the DC Load boot one) with other disc (a data disc) to load data for testing purpose. But when I change the disc and close the lid, Dreamcast tr...
- Thu Jun 22, 2017 7:12 pm
- Forum: Programming Discussion
- Topic: About GD Rom Drive reading a CD Rom
- Replies: 10
- Views: 2170
- Wed Jun 21, 2017 5:35 pm
- Forum: Programming Discussion
- Topic: About GD Rom Drive reading a CD Rom
- Replies: 10
- Views: 2170
Re: About GD Rom Drive reading a CD Rom
Ok so some questions about CD Rom : Reading ECMA specifications, it seems that all datas are located in the "Program area". I see on Wikipedia that a 700 M Bytes / 80 Minutes CD ROM holds 360000 sectors. Are all those sectors located only in the Program area or is it located in a region st...