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[/] [a-z80/] [trunk/] [cpu/] [control/] [execute.v] - Diff between revs 8 and 13

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Rev 8 Rev 13
Line 76... Line 76...
 
 
// Detects unknown instructions by signalling the known ones
// Detects unknown instructions by signalling the known ones
reg validPLA;                           // Valid PLA asserts this reg
reg validPLA;                           // Valid PLA asserts this reg
// Activates a state machine to compute WZ=IX+d; takes 5T cycles
// Activates a state machine to compute WZ=IX+d; takes 5T cycles
reg ixy_d;                              // Compute WX=IX+d
reg ixy_d;                              // Compute WX=IX+d
// Signals the setting of IX/IY and CB/ED prefix flags; inhibits clearing them
// Signals the setting of IX/IY prefix flags; inhibits clearing them
reg setIXIY;                            // Set IX/IY flag at the next T cycle
reg setIXIY;                            // Set IX/IY flag at the next T cycle
reg setCBED;                            // Set CB or ED flag at the next T cycle
 
// Holds asserted by non-repeating versions of block instructions (LDI/CPI,...)
// Holds asserted by non-repeating versions of block instructions (LDI/CPI,...)
reg nonRep;                             // Non-repeating block instruction
reg nonRep;                             // Non-repeating block instruction
// Suspends incrementing PC through address latch unless in HALT or interrupt mode
// Suspends incrementing PC through address latch unless in HALT or interrupt mode
reg pc_inc_hold;                        // Normally 0 unless in one of those modes
reg pc_inc_hold;                        // Normally 0 unless in one of those modes
 
 
Line 137... Line 136...
    // Reset global machine cycle functions
    // Reset global machine cycle functions
    fFetch = M1;                        // Fetch is aliased to M1
    fFetch = M1;                        // Fetch is aliased to M1
    fMRead = 0; fMWrite = 0; fIORead = 0; fIOWrite = 0;
    fMRead = 0; fMWrite = 0; fIORead = 0; fIOWrite = 0;
    ixy_d = 0;
    ixy_d = 0;
    setIXIY = 0;
    setIXIY = 0;
    setCBED = 0;
 
    nonRep = 0;
    nonRep = 0;
    pc_inc_hold = 0;
    pc_inc_hold = 0;
 
 
    //-------------------------------------------------------------------------
    //-------------------------------------------------------------------------
    // State-based signal assignment; code generated from Timings spreadsheet
    // State-based signal assignment; code generated from Timings spreadsheet

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