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//      Project:                        light8080 SOC           WiCores Solutions 

//

//      File name:                      intr_vec.h                      (March 03, 2012)

//

//      Writer:                         Moti Litochevski 

//

//      Description:

//              This file contains a simple example of calling interrupt service routine. this 

//              file defines the interrupt vector for external interrupt 0 located at address 

//              0x0008. the interrupts vectors addresses are set in the verilog interrupt 

//              controller "intr_ctrl.v" file. 

//              Code is generated for all 4 supported external interrupts but non used interrupt 

//              are not called. 

//              On execution of an interrupt the CPU will automatically clear the interrupt 

//              enable flag set by the EI instruction. the interrupt vectors in this example 

//              enable the interrupts again after interrupt service routine execution. to enable 

//              nested interrupts just move the EI instruction to the code executed before the 

//              call instruction to the service routine (see comments below). 

//              Note that this code is not optimized in any way. this is just an example to 

//              verify the interrupt mechanism of the light8080 CPU and show a simple example. 

//

//      Revision History:

//

//      Rev <revnumber>                 <Date>                  <owner> 

//              <comment>

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// to support interrupt enable the respective interrupt vector is defined here at the 

// beginning of the output assembly file. only the interrupt vector for used interrupts

// should call a valid interrupt service routine name defined in the C source file. the 

// C function name should be prefixed by "__". 

#asm

;Preserve space for interrupt routines

;interrupt 0 vector

        org #0008

        push af

        push bc

        push de

        push hl

;       ei                                      ; to enable nested interrupts uncomment this instruction

        call __int0_isr

        pop hl

        pop de

        pop bc

        pop af

        ei                                      ; interrupt are not enabled during the execution os the isr

        ret

;interrupt 1 vector

        org #0018

        push af

        push bc

        push de

        push hl

;       call __int1_isr         ; interrupt not used

        pop hl

        pop de

        pop bc

        pop af

        ei

        ret

;interrupt 2 vector

        org #0028

        push af

        push bc

        push de

        push hl

;       call __int2_isr         ; interrupt not used

        pop hl

        pop de

        pop bc

        pop af

        ei

        ret

;interrupt 3 vector

        org #0038

        push af

        push bc

        push de

        push hl

;       call __int3_isr         ; interrupt not used

        pop hl

        pop de

        pop bc

        pop af

        ei

        ret

#endasm 

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//                                              Th.. Th.. Th.. Thats all folks !!!

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