Rev |
Log message |
Author |
Age |
Path |
189 |
Merged changes from private repository,
added ceil_log2 function to Open8_pkg, since it is used to calculate RAM vectors,
cleaned up comments and removed local copies of the ceil_log2 function from peripherals. |
jshamlet |
1622d 18h |
/open8_urisc/trunk/VHDL/Open8_pkg.vhd |
188 |
Added a generic to alter the behavior of RTI so that it can optionally skip restoring the general purpose flags GP4 to GP7, allowing ISR's to make persistent changes to them. Also exported these flags to the top level for use outside the CPU. |
jshamlet |
1622d 20h |
/open8_urisc/trunk/VHDL/Open8_pkg.vhd |
187 |
Added the CPU_Halt input, only now as an input to the instruction decoder. The CPU_Halt line will assert the registered CPU_Halt_Req, which will cause the instruction decoder to abort the current instruction, reset the PC, then enter a hold state until the line is deasserted. Additionally, a very minor bug that could cause the SMSK instruction to effectively execute twice if interrupted was fixed. Lastly, cleaned up the comments even more. |
jshamlet |
1624d 17h |
/open8_urisc/trunk/VHDL/Open8_pkg.vhd |
186 |
Merged the interrupt override logic into the case structure, simplifying how interrupts are processed. |
jshamlet |
1627d 17h |
/open8_urisc/trunk/VHDL/Open8_pkg.vhd |
185 |
1) Fixed an apparently long-standing bug where the interrupt bit wasn't being cleared after an RTI
2) Modified the program counter logic to be simpler. It now always increments, and states control the increment using the offset field. A new set of constants was added to replace the old states.
3) Modified the ALU to always use Operand1 instead of ALU_Ctrl.Data (and removed the field in the record). A new ALU command, ALU_GMSK, was added, as it was the only instruction to set the .Data field to something other than Operand1 (Int_Mask)
4) Modified the package file so that flag names match what the assembler calls them. FL_Z is now PSR_Z, FL_GP1 is now PSR_GP4, etc.
5) Cleaned up the comments and code formatting |
jshamlet |
1627d 19h |
/open8_urisc/trunk/VHDL/Open8_pkg.vhd |
183 |
Renamed core to o8_cpu to match new naming scheme |
jshamlet |
1629d 20h |
/open8_urisc/trunk/VHDL/Open8_pkg.vhd |
182 |
Simplified the address generation logic at the expense of making LDX take one additional clock cycle. This allowed the address logic to be split out of the main state machine and simplified (greatly). During this process, a bug in SDO was found and fixed that caused it to return through the wrong pipe fill state wnen auto increment was disabled. |
jshamlet |
1629d 20h |
/open8_urisc/trunk/VHDL/Open8_pkg.vhd |
181 |
Altered the RSP instruction to allow the stack pointed to either be restored from registers or stored to registers based on the status of a processor bit. Also modified LDX to simplify the address logic. |
jshamlet |
1630d 16h |
/open8_urisc/trunk/VHDL/Open8_pkg.vhd |
172 |
General code cleanup |
jshamlet |
3154d 18h |
/open8_urisc/trunk/VHDL/Open8_pkg.vhd |
169 |
Corrected issue with CMP and SBC generating an inverted carry flag and added new constants to the package file to simplify interfacing new modules. |
jshamlet |
3209d 18h |
/open8_urisc/trunk/VHDL/Open8_pkg.vhd |
153 |
Fixed bug in interrupt logic that caused stack pointer to increment if interrupt occurred as specific instructions were being decoded,
Fixed bug in interrupt logic where instruction caching would remain enabled during an interrupt, causing improper execution depending on what instruction was in the decode stage as the interrupt is trigered. |
jshamlet |
4812d 09h |
/open8_urisc/trunk/VHDL/Open8_pkg.vhd |
151 |
Fixed STO instruction and interrupt logic to avoid address bus corruption issues. |
jshamlet |
4822d 13h |
/open8_urisc/trunk/VHDL/Open8_pkg.vhd |
10 |
corrected implementation for BTT to match V8/ARClite definition, changed sense of reset, corrected comments to match source values |
khays |
4963d 21h |
/open8_urisc/trunk/VHDL/Open8_pkg.vhd |
8 |
Need to learn SVN... |
jshamlet |
5292d 09h |
/open8_urisc/trunk/VHDL/Open8_pkg.vhd |
7 |
Initial Upload |
jshamlet |
5292d 09h |
/open8_urisc/trunk/open8_urisc/VHDL/Open8_pkg.vhd |