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-- HASM Example File

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.equ fpgabase      0xa0000000;

.equ membase       0x80000000;

.equ memfaultcount 0xa0000010;

.isr isr_handler;

start:

   call mem_test;

stophere:

    jmp stophere;

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-- mem_test shows how to implement a simple memory

-- test in hasm.

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mem_test:

   ld rega,membase;         -- Base address of memory

   ld regc,0x0;             -- Loop count

mem_write:

   ld regb,0x5a5a5a5a;      -- Test pattern A

   wr rega,regb;            -- Write rega to address pointed to by regb

   add rega,0x04;           -- Bump mem pointer

   ld regb,0xa5a5a5a5;      -- Test pattern B

   wr rega,regb;            -- Write rega to address pointed to by regb

   add rega,0x04;           -- Bump mem pointer

   add regc,0x01;           -- Bump loop count

   cmp_e regc,0x100;        -- Done writing?

   jmp mem_write;           -- No, keep going

   ld rega,membase;         -- Finished writing so reinit for a read

   ld regc,0x0;             -- Reinit the loop pointer

mem_verify:

   rd regb,rega;            -- Read back first location

   cmp_e regb,0x5a5a5a5a;   -- First value ok?

   call mem_fault;          -- Values didn't match so call fault handler

   add rega,0x4;            -- Bump the address pointer

   rd regb,rega;            -- Get the next value

   cmp_e regb,0xa5a5a5a5;   -- Check against second patter

   call mem_fault;          -- Didn't match, call the handler

   add regc,0x1;            -- Bump the iteration count

   cmp_e regc,0x100;        -- Done yet?

   jmp mem_verify;          -- No, keep going

   ret;                     -- Yep return

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-- mem_fault is responsible for incrementing the

-- fault count stored in the FPGA.

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mem_fault:

   push rega;               -- Save rega

   rd rega,memfaultcount;   -- Get the fault count

   add rega,0x1;            -- Increment the fault count

   wr rega,memfaultcount;   -- Write the fault count back

   pop rega;                -- Restore rega

   ret;                     -- Return to caller

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-- isr_handler gets called when then the

-- machine_interrupt input to the cycle_simulator

-- file is brought high.

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isr_handler:

   push regd;

   pop regd;

   ret;