URL
https://opencores.org/ocsvn/light8080/light8080/trunk
Subversion Repositories light8080
Compare Revisions
- This comparison shows the changes necessary to convert path
/light8080
- from Rev 47 to Rev 48
- ↔ Reverse comparison
Rev 47 → Rev 48
/trunk/ucode/light8080.m80
14,10 → 14,10
// and writes it back somewhere; and the flags group all other microinstruction |
// control signals. |
// |
// For any given instruction, operation 2 takes place in the cycle following |
// operation 1. It happens concurrently with the next instruction's operation 1, |
// so whenever a register is written to in an operation 2 it will NOT be |
// available for the next instruction. |
// For any given microinstruction, operation 2 takes place in the cycle after |
// operation 1. It happens concurrently with the next microinstruction's |
// operation 1, so whenever a register is written to in an operation 2 it will |
// NOT be available for the next microinstruction. |
// |
// In operation 1, you may load any one of T1 or T2 from the register bank or |
// from DI which is simply the unregistered signal data_in. |
51,9 → 51,9
// #ret : Jump to address saved by the last JST or TJSR m.i. |
// #rd : Activate rd signal for the 2nd cycle. |
// #wr : Activate wr signal for the 2nd cycle. |
// #fp_r : This instruction updates all PSW flags except for C. |
// #fp_c : This instruction updates only the C flag in the PSW. |
// #fp_rc : This instruction updates all the flags in the PSW. |
// #fp_r : This microinstruction updates all PSW flags except for C. |
// #fp_c : This microinstruction updates only the C flag in the PSW. |
// #fp_rc : This microinstruction updates all the flags in the PSW. |
// #clrt1 : Clear T1 at the end of 1st cycle. |
// #io : Activate io signal for 1st cycle. |
// #ei : Set interrupt enable register. |
536,7 → 536,7
JSR push |
NOP ; _pl = rst ; #clrt1 |
NOP ; _ph = AND ; #end // T1 & T2 = 0, because T2=0 |
// No extra cycle needed, _ph is not used in the next instruction |
// No extra cycle needed, _ph is not used in the next microinstruction |
|
__code "11101001" |
__asm PCHL |