| Rev |
Log message |
Author |
Age |
Path |
| 186 |
Merged the interrupt override logic into the case structure, simplifying how interrupts are processed. |
jshamlet |
1748d 14h |
/open8_urisc/trunk/VHDL/o8_cpu.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 |
1748d 16h |
/open8_urisc/trunk/VHDL/o8_cpu.vhd |
| 183 |
Renamed core to o8_cpu to match new naming scheme |
jshamlet |
1750d 17h |
/open8_urisc/trunk/VHDL/o8_cpu.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 |
1750d 17h |
/open8_urisc/trunk/VHDL/Open8.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 |
1751d 13h |
/open8_urisc/trunk/VHDL/Open8.vhd |
| 172 |
General code cleanup |
jshamlet |
3275d 15h |
/open8_urisc/trunk/VHDL/Open8.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 |
3330d 15h |
/open8_urisc/trunk/VHDL/Open8.vhd |
| 168 |
Simplified write data path logic,
Converted RTC to packed BCD,
Corrected several bugs in real time clock component, |
jshamlet |
4109d 12h |
/open8_urisc/trunk/VHDL/Open8.vhd |
| 167 |
Updated CPU model; Pipelined ALU control signals to improve fMAX, corrected issue with interrupt controller priority not being obeyed, fixed bug in auto-indexing instructions where the upper register wasn't being properly incremented, cleaned up code to make the processor model easier to follow.
Added several useful modules that use the Open8 bus. |
jshamlet |
4117d 10h |
/open8_urisc/trunk/VHDL/Open8.vhd |
| 164 |
Modified the data path to allow the bus to go idle while waiting for an interrupt. This makes it easier to debug code that uses the WAI instruction, as both Wr_Enable and Rd_Enable go low. |
jshamlet |
4753d 06h |
/open8_urisc/trunk/VHDL/Open8.vhd |
| 162 |
Added optional generic to specify that the BRK instruction implements a WAit_for_Interrupt (WAI) instruction instead. Logically emulates INT, but without triggering a soft interrupt. Note that the NOP instruction maps to BRK, and will not function correctly if this option is set. |
jshamlet |
4843d 23h |
/open8_urisc/trunk/VHDL/Open8.vhd |
| 156 |
Optimized for timing,
Flattened block structure to single entity. |
jshamlet |
4900d 13h |
/open8_urisc/trunk/VHDL/Open8.vhd |
| 155 |
Fixed additional interrupt logic bug,
Optimized several blocks - including ALU, stack, program counter, and data path. |
jshamlet |
4901d 08h |
/open8_urisc/trunk/VHDL/Open8.vhd |
| 154 |
Fixed problem with missing data path override in interrupt logic. Should resolve issues with processor crashing when an interrupt occurs as a STO instruction is being executed. |
jshamlet |
4906d 11h |
/open8_urisc/trunk/VHDL/Open8.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 |
4933d 07h |
/open8_urisc/trunk/VHDL/Open8.vhd |
| 151 |
Fixed STO instruction and interrupt logic to avoid address bus corruption issues. |
jshamlet |
4943d 10h |
/open8_urisc/trunk/VHDL/Open8.vhd |
| 10 |
corrected implementation for BTT to match V8/ARClite definition, changed sense of reset, corrected comments to match source values |
khays |
5084d 18h |
/open8_urisc/trunk/VHDL/Open8.vhd |
| 8 |
Need to learn SVN... |
jshamlet |
5413d 06h |
/open8_urisc/trunk/VHDL/Open8.vhd |
| 7 |
Initial Upload |
jshamlet |
5413d 06h |
/open8_urisc/trunk/open8_urisc/VHDL/Open8.vhd |
