Cons
This commit is contained in:
Simon Forman
parent
d67420ae68
commit
4c13868e7c
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@ -93,13 +93,62 @@ program([ % Mainloop.
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% TOS has the offset from new stack cell to term cell.
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% Combine with the offset to the previous stack cell.
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lsl_imm(TOS, TOS, 15), % TOS := TOS << 15
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ior(TOS, TOS, 4), % TOS := TOS | 4
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ior_imm(TOS, TOS, 4), % TOS := TOS | 4
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% label(DONE),
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label(Done),
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store_word(TOS, SP, 0), % RAM[SP] := TOS
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do_offset(Main),
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label(HALT),
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do_offset(HALT)
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label(HALT), % This is a HALT loop, the emulator detects and traps
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do_offset(HALT), % on this "10 goto 10" instruction.
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% ======================================
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label(Cons), % Let's cons.
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ror_imm(TEMP0, TOS, 15), % TEMP0 := TOS >> 15
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add(TEMP0, TEMP0, SP), % TEMP0 = SP + TOS[30:15]
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% TEMP0 = Address of the list to which to append.
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and_imm(TOS, TOS, 0x7fff), % get the offset of the tail of the stack
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add(TOS, TOS, SP), % TOS = SP + TOS[15:0]
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% TOS = Address of the second stack cell.
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% the address of the second item on the stack is (TOS) + ram[TOS][30:15]
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% the address of the third stack cell is (TOS) + ram[TOS][15: 0]
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load_word(TEMP1, TOS, 0),
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% TEMP1 contains the record of the second stack cell.
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% the address of the second item on the stack is (TOS) + TEMP1[30:15]
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% the address of the third stack cell is (TOS) + TEMP1[15: 0]
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ror_imm(TEMP2, TEMP1, 15), % TEMP2 := TEMP1 >> 15
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add(TEMP2, TEMP2, TOS),
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% TEMP2 contains the address of the second item on the stack
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and_imm(TEMP3, TEMP1, 0x7fff), % get the offset of the third stack cell
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add(TEMP3, TEMP1, TOS),
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% TEMP3 = TOS + TEMP1[15:0] the address of the third stack cell
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sub_imm(SP, SP, 4),
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sub(TEMP2, TEMP2, SP),
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sub(TEMP0, TEMP0, SP),
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lsl_imm(TEMP2, TEMP2, 15), % TEMP2 := TEMP2 << 15
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ior(TEMP2, TEMP2, TEMP0),
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store_word(TEMP2, SP, 0),
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% Now reuse TEMP0 and put the next record in TOS.
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sub_imm(SP, SP, 4),
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sub(TEMP0, TEMP0, SP),
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mov_imm_with_shift(TOS, 2), % TOS := 4 << 15
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ior(TOS, TOS, TEMP0),
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% store_word(TOS, SP, 0),
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do_offset(Done)
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]) :- [SP, EXPR_addr, TOS, TERM, EXPR, TermAddr, TEMP0]=[0, 1, 2, 3, 4, 5, 6].
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@ -198,3 +198,79 @@ So now that i've recreated it, what is it doing?
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This blows, just write it in assembly already.
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-------------------------------
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TO review, at this point, when we jump to the machine code of a
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definition, the following registers hold:
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EXPR - the record word of the expression.
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EXPR_addr - the address of the next cell of the expression list.
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TERM - the term's record word.
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TermAddr - the address of the term.
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SP - points to TOS record in RAM
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TOS - the record word of TOS
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address of the list to append to is SP + TOS[30:15]
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the address of the second stack cell is SP + TOS[15:0]
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the address of the second item on the stack is (SP + TOS[15:0]) + ram[SP + TOS[15:0]][30:15]
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the address of the third stack cell is (SP + TOS[15:0]) + ram[SP + TOS[15:0]][15: 0]
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we need to create
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[SP - 4] -> 00:(address of the second item on the stack):(address of the list to append to)
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[SP - 8] -> 00:(address of the record above) :(address of the third stack cell)
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Each of the addresses above must be converted to offsets from their
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respective records.
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ror_imm(TEMP0, TOS, 15), % TEMP0 := TOS >> 15
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add(TEMP0, TEMP0, SP)
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% TEMP0 = SP + TOS[30:15] Address of the list to which to append.
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and_imm(TOS, TOS, 0x7fff), % get the offset of the tail of the stack
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add(TOS, TOS, SP)
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% TOS = SP + TOS[15:0] Address of the second stack cell.
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% the address of the second item on the stack is (TOS) + ram[TOS][30:15]
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% the address of the third stack cell is (TOS) + ram[TOS][15: 0]
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load_word(TEMP1, TOS, 0), % TOS := TOS << 15
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% TEMP1 contains the record of the second stack cell.
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% the address of the second item on the stack is (TOS) + TEMP1[30:15]
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% the address of the third stack cell is (TOS) + TEMP1[15: 0]
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ror_imm(TEMP2, TEMP1, 15), % TEMP2 := TEMP1 >> 15
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add(TEMP2, TEMP2, TOS)
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% TEMP2 contains the address of the second item on the stack
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and_imm(TEMP3, TEMP1, 0x7fff), % get the offset of the third stack cell
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add(TEMP3, TEMP1, TOS)
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% TEMP3 = TOS + TEMP1[15:0] the address of the third stack cell
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we need to create
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[SP - 4] -> 00:(address of the second item on the stack):(address of the list to append to)
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[SP - 8] -> 00:(address of the record above) :(address of the third stack cell)
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4 << 15
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Each of the addresses above must be converted to offsets from their
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respective records.
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sub_imm(SP, SP, 4),
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sub(TEMP2, TEMP2, SP),
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sub(TEMP0, TEMP0, SP),
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lsl_imm(TEMP2, TEMP2, 15), % TEMP2 := TEMP2 << 15
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ior(TEMP2, TEMP2, TEMP0),
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store_word(TEMP2, SP, 0),
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sub_imm(SP, SP, 4),
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sub(TEMP3, TEMP3, SP),
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mov_imm(TEMP2, 4),
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lsl_imm(TEMP2, TEMP2, 15), % TEMP2 := 4 << 15
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ior(TEMP2, TEMP2, TEMP3),
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store_word(TEMP2, SP, 0),
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