Implement line reading in calculator.asm
This commit is contained in:
Juhani Krekelä
parent
7a4c6295f3
commit
a993cab542
198
calculator.asm
198
calculator.asm
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@ -1,21 +1,143 @@
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org 0
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start:
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load r0, lit01
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load r1, litff
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cleq r0, r0, pushWord
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cleq r0, r0, stPrinthex
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xor r0, r0
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load r1, lit41
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cleq r0, r0, pushWord
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cleq r0, r0, stPrinthex
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cleq r0, r0, stSub
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cleq r0, r0, stPrinthex
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cleq r0, r0, stReadline
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cleq r0, r0, dumpstack
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halt
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dumpstack:
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load r0, SPStart+0
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load r1, SPStart+1
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store dumpstackPtr+0, r0
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store dumpstackPtr+1, r1
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dumpstackLoop:
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load r0, dumpstackPtr+0
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load r1, dumpstackPtr+1
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load r2, SP+0
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load r3, SP+1
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brneq r0, r2, dumpstackDumpword
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breq r1, r3, dumpstackEnd
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dumpstackDumpword:
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load r0, dumpstackPtr+0
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load r1, dumpstackPtr+1
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store loadByteHigh, r0
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store loadByteLow, r1
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cleq r0, r0, loadByte
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cleq r0, r0, writehexByte
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load r0, dumpstackPtr+0
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load r1, dumpstackPtr+1
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cleq r0, r0, incWord
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store dumpstackPtr+0, r0
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store dumpstackPtr+1, r1
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load r0, dumpstackPtr+0
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load r1, dumpstackPtr+1
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store loadByteHigh, r0
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store loadByteLow, r1
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cleq r0, r0, loadByte
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cleq r0, r0, writehexByte
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load r0, dumpstackPtr+0
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load r1, dumpstackPtr+1
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cleq r0, r0, incWord
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store dumpstackPtr+0, r0
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store dumpstackPtr+1, r1
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load r0, litcharSpace
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store ffff, r0
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breq r0, r0, dumpstackLoop
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dumpstackEnd:
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breq r0, r0, newline
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dumpstackPtr: addr dumpstackPtr
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stReadline:
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; Current index starts at 0
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xor r0, r0
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xor r1, r1
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cleq r0, r0, pushWord
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readlineLoop:
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; Read a byte of input
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cleq r0, r0, stKey
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; Is it enter?
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cleq r0, r0, peekWord
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load r0, litcharCR
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breq r0, r1, readlineEnter
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; Is it backspace?
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load r0, litcharBS
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breq r0, r1, readlineBackspace
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; Is the buffer full?
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cleq r0, r0, stOver
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load r0, linebufSize+0
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load r1, linebufSize+1
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cleq r0, r0, pushWord
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cleq r0, r0, stGtEq
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brneq r0, r1, readlineBufFull
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; Calculate address
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cleq r0, r0, stOver
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load r0, linebufStart+0
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load r1, linebufStart+1
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cleq r0, r0, pushWord
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cleq r0, r0, stAdd
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; Store the read byte
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cleq r0, r0, stStoreByte
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; Increase index
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cleq r0, r0, stInc
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breq r0, r0, readlineLoop
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readlineEnter:
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; Remove the CR byte off the stack, as we only want to return the length
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cleq r0, r0, popWord
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breq r0, r0, newline
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readlineBackspace:
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; Remove the BS byte off the stack
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cleq r0, r0, popWord
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; Are we at the beginning of the line?
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cleq r0, r0, stDup
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xor r0, r0
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xor r1, r1
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cleq r0, r0, pushWord
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cleq r0, r0, stSwap
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cleq r0, r0, stGtEq
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brneq r0, r1, readlineLoop
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; Decrease the index and erase the echoed character
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cleq r0, r0, stDec
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load r3, litcharSpace
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store ffff, r3
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load r3, litcharBS
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store ffff, r3
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breq r0, r0, readlineLoop
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readlineBufFull:
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; Drop the input byte and erase the echoed character
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cleq r0, r0, popWord
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load r3, litcharBS
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store ffff, r3
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load r3, litcharSpace
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store ffff, r3
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load r3, litcharBS
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store ffff, r3
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breq r0, r0, readlineLoop
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; ==================================================================
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; Stack-based functions
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; ==================================================================
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@ -42,6 +164,18 @@ stSub:
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cleq r0, r0, subWord
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breq r0, r0, pushWord
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; a -- a+1
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stInc:
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cleq r0, r0, popWord
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cleq r0, r0, incWord
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breq r0, r0, pushWord
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; a -- a-1
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stDec:
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cleq r0, r0, popWord
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cleq r0, r0, decWord
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breq r0, r0, pushWord
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; a b --
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; if a >= b then r0:r1 = 0001
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; else r0:r1 = 0000
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@ -98,6 +232,31 @@ stOver:
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cleq r0, r0, tmp2LoadWord01
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breq r0, r0, pushWord
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; a b -- b a
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stSwap:
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cleq r0, r0, popWord
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cleq r0, r0, tmpStoreWord01
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cleq r0, r0, popWord
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cleq r0, r0, tmp2StoreWord01
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cleq r0, r0, tmpLoadWord01
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cleq r0, r0, pushWord
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cleq r0, r0, tmp2LoadWord01
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breq r0, r0, pushWord
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; ------------------------------------------------------------------
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; Memory
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; ------------------------------------------------------------------
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; a p --
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stStoreByte:
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cleq r0, r0, popWord
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store storeByteHigh, r0
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store storeByteLow, r1
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cleq r0, r0, popWord
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xor r0, r0
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or r0, r1
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breq r0, r0, storeByte
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; ==================================================================
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; Low-level functions
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; ==================================================================
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@ -727,6 +886,9 @@ lit0d: data 0d
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lit0e: data 0e
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lit0f: data 0f
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litcharSpace:
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lit20: data 20
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litchar0:
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lit30: data 30
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litchar1:
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@ -783,8 +945,14 @@ lit72: data 72
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litff: data ff
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; ==================================================================
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; Stack
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; Data
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; ==================================================================
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SP: addr stackBase
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stackBase:
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linebufStart: addr end
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linebufSize:
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data 00
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data 80
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SP: addr end + 80
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SPStart: addr end + 80
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end:
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