586 lines
30 KiB
Plaintext
586 lines
30 KiB
Plaintext
# Port of https://github.com/akkartik/crenshaw/blob/master/tutor2.1.pas
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# which corresponds to the section "single digits" in https://compilers.iecc.com/crenshaw/tutor2.txt
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# except that we support hex digits.
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#
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# To run (from the subx/ directory):
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# $ ./subx translate *.subx apps/crenshaw2-1.subx -o apps/crenshaw2-1
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# $ echo '3' |./subx run apps/crenshaw2-1
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# Expected output:
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# # syscall(exit, 3)
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# bb/copy-to-EBX 3/imm32
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# b8/copy-to-EAX 1/imm32/exit
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# cd/syscall 0x80/imm8
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#
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# To run the generated output:
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# $ echo '3' |./subx run apps/crenshaw2-1 > z1.subx
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# $ ./subx translate z1.subx -o z1
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# $ ./subx run z1
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# $ echo $?
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# 3
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#
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# Stdin must contain just a single hex digit. Other input will print an error:
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# $ echo 'xyz' |./subx run apps/crenshaw2-1
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# Error: integer expected
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#
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# Names in this file sometimes follow Crenshaw's original rather than my usual
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# naming conventions.
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== code
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# instruction effective address register displacement immediate
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# . op subop mod rm32 base index scale r32
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# . 1-3 bytes 3 bits 2 bits 3 bits 3 bits 3 bits 2 bits 2 bits 0/1/2/4 bytes 0/1/2/4 bytes
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Entry: # run tests if necessary, call 'compile' if not
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# initialize heap
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# . Heap = new-segment(64KB)
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# . . push args
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68/push Heap/imm32
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68/push 0x10000/imm32/64KB
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# . . call
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e8/call new-segment/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
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# . prolog
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89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
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# - if argc > 1 and argv[1] == "test", then return run_tests()
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# . argc > 1
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81 7/subop/compare 1/mod/*+disp8 5/rm32/EBP . . . . 0/disp8 1/imm32 # compare *EBP
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7e/jump-if-lesser-or-equal $run-main/disp8
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# . argv[1] == "test"
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# . . push args
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68/push "test"/imm32
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ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8)
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# . . call
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e8/call kernel-string-equal?/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
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# . check result
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3d/compare-EAX-and 1/imm32
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75/jump-if-not-equal $run-main/disp8
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# . run-tests()
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e8/call run-tests/disp32
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8b/copy 0/mod/indirect 5/rm32/.disp32 . . 3/r32/EBX Num-test-failures/disp32 # copy *Num-test-failures to EBX
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eb/jump $main:end/disp8
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$run-main:
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# - otherwise read a program from stdin and emit its translation to stdout
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# var ed/EAX : exit-descriptor
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81 5/subop/subtract 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # subtract from ESP
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89/copy 3/mod/direct 0/rm32/EAX . . . 4/r32/ESP . . # copy ESP to EAX
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# configure ed to really exit()
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# . ed->target = 0
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c7 0/subop/copy 0/mod/direct 0/rm32/EAX . . . . . 0/imm32 # copy to *EAX
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# return compile(Stdin, 1/stdout, 2/stderr, ed)
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# . . push args
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50/push-EAX/ed
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68/push 2/imm32/stderr
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68/push 1/imm32/stdout
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68/push Stdin/imm32
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# . . call
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e8/call compile/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0x10/imm32 # add to ESP
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# . syscall(exit, 0)
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bb/copy-to-EBX 0/imm32
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$main:end:
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b8/copy-to-EAX 1/imm32/exit
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cd/syscall 0x80/imm8
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# the main entry point
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compile: # in : (address buffered-file), out : fd or (address stream), err : fd or (address stream), ed : (address exit-descriptor) -> <void>
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# . prolog
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55/push-EBP
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89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
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# . save registers
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50/push-EAX
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51/push-ECX
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# prime the pump
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# . Look = get-char(in)
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# . . push args
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ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8)
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# . . call
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e8/call get-char/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
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# var num/ECX : (address stream) on the stack
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# Numbers can be 32 bits or 8 hex bytes long. One of them will be in 'Look', so we need space for 7 bytes.
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# Sizing the stream just right buys us overflow-handling for free inside 'get-num'.
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# Add 12 bytes for 'read', 'write' and 'length' fields, for a total of 19 bytes, or 0x13 in hex.
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# The stack pointer is no longer aligned, so dump_stack() can be misleading past this point.
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81 5/subop/subtract 3/mod/direct 4/rm32/ESP . . . . . 0x13/imm32 # subtract from ESP
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89/copy 3/mod/direct 1/rm32/ECX . . . 4/r32/ESP . . # copy ESP to ECX
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# initialize the stream
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# . num->length = 7
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c7 0/subop/copy 1/mod/*+disp8 1/rm32/ECX . . . . 8/disp8 7/imm32 # copy to *(ECX+8)
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# . clear-stream(num)
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# . . push args
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51/push-ECX
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# . . call
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e8/call clear-stream/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
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# read a digit from 'in' into 'num'
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# . get-num(in, num, err, ed)
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# . . push args
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ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0x14/disp8 . # push *(EBP+20)
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ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0x10/disp8 . # push *(EBP+16)
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51/push-ECX/num
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ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8)
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# . . call
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e8/call get-num/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0x10/imm32 # add to ESP
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# render 'num' into the following template on 'out':
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# bb/copy-to-EBX _num_
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# b8/copy-to-EAX 1/imm32/exit
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# cd/syscall 0x80/imm8
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#
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# . write(out, "bb/copy-to-EBX ")
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# . . push args
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68/push "bb/copy-to-EBX "/imm32
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ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
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# . . call
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e8/call write/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
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# . write-stream(out, num)
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# . . push args
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51/push-ECX/num
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ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
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# . . call
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e8/call write-stream/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
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# . write(out, Newline)
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# . . push args
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68/push Newline/imm32
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ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
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# . . call
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e8/call write/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
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# . write(out, "b8/copy-to-EAX 1/imm32/exit\n")
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# . . push args
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68/push "b8/copy-to-EAX 1/imm32/exit\n"/imm32
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ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
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# . . call
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e8/call write/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
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# . write(out, "cd/syscall 0x80/imm8\n")
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# . . push args
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68/push "cd/syscall 0x80/imm8\n"/imm32
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ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
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# . . call
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e8/call write/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
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$compile:end:
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# . restore registers
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59/pop-to-ECX
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58/pop-to-EAX
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# . epilog
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89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP
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5d/pop-to-EBP
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c3/return
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# Read a single digit into 'out'. Abort if there are none, or if there is no space in 'out'.
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# Input comes from the global variable 'Look', and we leave the next byte from
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# 'in' into it on exit.
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get-num: # in : (address buffered-file), out : (address stream), err : fd or (address stream), ed : (address exit-descriptor) -> <void>
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# pseudocode:
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# if (!is-digit?(Look)) expected(ed, err, "integer")
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# if out->write >= out->length
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# write(err, "Error: too many digits in number\n")
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# stop(ed, 1)
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# out->data[out->write] = LSB(Look)
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# ++out->write
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# Look = get-char(in)
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#
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# registers:
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# in: ESI
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# out: EDI
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# out->write: ECX (cached copy; need to keep in sync)
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# out->length: EDX
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# temporaries: EAX, EBX
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# We can't allocate Look to a register because it gets written implicitly in
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# get-char in each iteration of the loop. (Thereby demonstrating that it's
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# not the right interface for us. But we'll keep it just to follow Crenshaw.)
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#
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# . prolog
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55/push-EBP
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89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
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# - if (is-digit?(Look)) expected(ed, err, "integer")
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# . EAX = is-digit?(Look)
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# . . push args
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ff 6/subop/push 0/mod/indirect 5/rm32/.disp32 . . . Look/disp32 . # push *Look
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# . . call
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e8/call is-digit?/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
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# . if (EAX == 0)
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3d/compare-EAX-and 0/imm32
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75/jump-if-not-equal $get-num:main/disp8
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# . expected(ed, err, "integer")
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# . . push args
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68/push "integer"/imm32
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ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0x10/disp8 . # push *(EBP+16)
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ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0x14/disp8 . # push *(EBP+20)
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# . . call
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e8/call expected/disp32 # never returns
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP
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$get-num:main:
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# - otherwise read a digit
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# . save registers
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50/push-EAX
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51/push-ECX
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52/push-EDX
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53/push-EBX
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56/push-ESI
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57/push-EDI
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# read necessary variables to registers
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# ESI = in
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8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 6/r32/ESI 8/disp8 . # copy *(EBP+8) to ESI
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# EDI = out
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8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 7/r32/EDI 0xc/disp8 . # copy *(EBP+12) to EDI
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# ECX = out->write
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8b/copy 0/mod/indirect 7/rm32/EDI . . . 1/r32/ECX . . # copy *EDI to ECX
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# EDX = out->length
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8b/copy 1/mod/*+disp8 7/rm32/EDI . . . 2/r32/EDX 8/disp8 . # copy *(EDI+8) to EDX
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# if (out->write >= out->length) error
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39/compare 3/mod/direct 2/rm32/EDX . . . 1/r32/ECX . . # compare EDX with ECX
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7d/jump-if-lesser $get-num:stage2/disp8
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# . error(ed, err, msg) # TODO: show full number
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# . . push args
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68/push "get-num: too many digits in number"/imm32
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ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0x10/disp8 . # push *(EBP+16)
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ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0x14/disp8 . # push *(EBP+20)
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# . . call
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e8/call error/disp32 # never returns
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP
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$get-num:stage2:
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# out->data[out->write] = LSB(Look)
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8d/copy-address 1/mod/*+disp8 4/rm32/sib 7/base/EDI 1/index/ECX . 3/r32/EBX 0xc/disp8 . # copy EDI+ECX+12 to EBX
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8b/copy 0/mod/indirect 5/rm32/.disp32 . . 0/r32/EAX Look/disp32 . # copy *Look to EAX
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88/copy-byte 0/mod/indirect 3/rm32/EBX . . . 0/r32/AL . . # copy byte at AL to *EBX
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# ++out->write
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41/increment-ECX
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# Look = get-char(in)
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# . . push args
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56/push-ESI
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# . . call
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e8/call get-char/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
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$get-num:loop-end:
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# persist necessary variables from registers
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89/copy 0/mod/indirect 7/rm32/EDI . . . 1/r32/ECX . . # copy ECX to *EDI
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$get-num:end:
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# . restore registers
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5f/pop-to-EDI
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5e/pop-to-ESI
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5b/pop-to-EBX
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5a/pop-to-EDX
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59/pop-to-ECX
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58/pop-to-EAX
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# . epilog
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89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP
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5d/pop-to-EBP
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c3/return
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test-get-num-reads-single-digit:
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# - check that get-num returns first character if it's a digit
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# This test uses exit-descriptors. Use EBP for setting up local variables.
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55/push-EBP
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89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
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# clear all streams
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# . clear-stream(_test-stream)
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# . . push args
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68/push _test-stream/imm32
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# . . call
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e8/call clear-stream/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
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# . clear-stream(_test-buffered-file+4)
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# . . push args
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b8/copy-to-EAX _test-buffered-file/imm32
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05/add-to-EAX 4/imm32
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50/push-EAX
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# . . call
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e8/call clear-stream/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
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# . clear-stream(_test-output-stream)
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# . . push args
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68/push _test-output-stream/imm32
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# . . call
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e8/call clear-stream/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
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# . clear-stream(_test-error-stream)
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# . . push args
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68/push _test-error-stream/imm32
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# . . call
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e8/call clear-stream/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
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# initialize 'in'
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# . write(_test-stream, "3")
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# . . push args
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68/push "3"/imm32
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68/push _test-stream/imm32
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# . . call
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e8/call write/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
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# initialize exit-descriptor 'ed' for the call to 'get-num' below
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# . var ed/EAX : exit-descriptor
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81 5/subop/subtract 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # subtract from ESP
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89/copy 3/mod/direct 0/rm32/EAX . . . 4/r32/ESP . . # copy ESP to EAX
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# . tailor-exit-descriptor(ed, 16)
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# . . push args
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68/push 0x10/imm32/nbytes-of-args-for-get-num
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50/push-EAX/ed
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# . . call
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e8/call tailor-exit-descriptor/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
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# prime the pump
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# . get-char(_test-buffered-file)
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# . . push args
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68/push _test-buffered-file/imm32
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# . . call
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e8/call get-char/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
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# get-num(in, out, err, ed)
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# . . push args
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50/push-EAX/ed
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68/push _test-error-stream/imm32
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68/push _test-output-stream/imm32
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68/push _test-buffered-file/imm32
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# . . call
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e8/call get-num/disp32
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# registers except ESP may be clobbered at this point
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0x10/imm32 # add to ESP
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# check-ints-equal(*_test-output-stream->data, '3', msg)
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# . . push args
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68/push "F - test-get-num-reads-single-digit"/imm32
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68/push 0x33/imm32
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b8/copy-to-EAX _test-output-stream/imm32
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ff 6/subop/push 1/mod/*+disp8 0/rm32/EAX . . . . 0xc/disp8 . # push *(EAX+12)
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# . . call
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e8/call check-ints-equal/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP
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|
# . reclaim locals
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|
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
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|
5d/pop-to-EBP
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|
c3/return
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test-get-num-aborts-on-non-digit-in-Look:
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# - check that get-num returns first character if it's a digit
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# This test uses exit-descriptors. Use EBP for setting up local variables.
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55/push-EBP
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|
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
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|
# clear all streams
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|
# . clear-stream(_test-stream)
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# . . push args
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68/push _test-stream/imm32
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|
# . . call
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e8/call clear-stream/disp32
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# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
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|
# . clear-stream(_test-buffered-file+4)
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|
# . . push args
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|
b8/copy-to-EAX _test-buffered-file/imm32
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05/add-to-EAX 4/imm32
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50/push-EAX
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|
# . . call
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e8/call clear-stream/disp32
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|
# . . discard args
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81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
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|
# . clear-stream(_test-output-stream)
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|
# . . push args
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|
68/push _test-output-stream/imm32
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|
# . . call
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e8/call clear-stream/disp32
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|
# . . discard args
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|
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
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|
# . clear-stream(_test-error-stream)
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|
# . . push args
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|
68/push _test-error-stream/imm32
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|
# . . call
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e8/call clear-stream/disp32
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|
# . . discard args
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|
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
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|
# initialize 'in'
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|
# . write(_test-stream, "3")
|
|
# . . push args
|
|
68/push "3"/imm32
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|
68/push _test-stream/imm32
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|
# . . call
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|
e8/call write/disp32
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|
# . . discard args
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|
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
|
|
# initialize exit-descriptor 'ed' for the call to 'get-num' below
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|
# . var ed/EAX : (address exit-descriptor)
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|
81 5/subop/subtract 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # subtract from ESP
|
|
89/copy 3/mod/direct 0/rm32/EAX . . . 4/r32/ESP . . # copy ESP to EAX
|
|
# . tailor-exit-descriptor(ed, 16)
|
|
# . . push args
|
|
68/push 0x10/imm32/nbytes-of-args-for-get-num
|
|
50/push-EAX/ed
|
|
# . . call
|
|
e8/call tailor-exit-descriptor/disp32
|
|
# . . discard args
|
|
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
|
|
# *don't* prime the pump
|
|
# get-num(in, out, err, ed)
|
|
# . . push args
|
|
50/push-EAX/ed
|
|
68/push _test-error-stream/imm32
|
|
68/push _test-output-stream/imm32
|
|
68/push _test-buffered-file/imm32
|
|
# . . call
|
|
e8/call get-num/disp32
|
|
# registers except ESP may be clobbered at this point
|
|
# . . discard args
|
|
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0x10/imm32 # add to ESP
|
|
# check that get-num tried to call exit(1)
|
|
# . check-ints-equal(ed->value, 2, msg) # i.e. stop was called with value 1
|
|
# . . push args
|
|
68/push "F - test-get-num-aborts-on-non-digit-in-Look"/imm32
|
|
68/push 2/imm32
|
|
# . . push ed->value
|
|
ff 6/subop/push 1/mod/*+disp8 0/rm32/EAX . . . . 4/disp8 . # push *(EAX+4)
|
|
# . . call
|
|
e8/call check-ints-equal/disp32
|
|
# . . discard args
|
|
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP
|
|
# . reclaim locals
|
|
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
|
|
5d/pop-to-EBP
|
|
c3/return
|
|
|
|
## helpers
|
|
|
|
# write(f, "Error: "+s+" expected\n") then stop(ed, 1)
|
|
expected: # ed : (address exit-descriptor), f : fd or (address stream), s : (address array byte) -> <void>
|
|
# . prolog
|
|
55/push-EBP
|
|
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
|
|
# write(f, "Error: ")
|
|
# . . push args
|
|
68/push "Error: "/imm32
|
|
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
|
|
# . . call
|
|
e8/call write/disp32
|
|
# . . discard args
|
|
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
|
|
# write(f, s)
|
|
# . . push args
|
|
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0x10/disp8 . # push *(EBP+16)
|
|
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
|
|
# . . call
|
|
e8/call write/disp32
|
|
# . . discard args
|
|
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
|
|
# write(f, " expected")
|
|
# . . push args
|
|
68/push " expected\n"/imm32
|
|
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 . # push *(EBP+12)
|
|
# . . call
|
|
e8/call write/disp32
|
|
# . . discard args
|
|
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
|
|
# stop(ed, 1)
|
|
# . . push args
|
|
68/push 1/imm32
|
|
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8)
|
|
# . . call
|
|
e8/call stop/disp32
|
|
# should never get past this point
|
|
$expected:dead-end:
|
|
# . epilog
|
|
89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP
|
|
5d/pop-to-EBP
|
|
c3/return
|
|
|
|
# read a byte from 'f', and save it in 'Look'
|
|
get-char: # f : (address buffered-file) -> <void>
|
|
# . prolog
|
|
55/push-EBP
|
|
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
|
|
# . save registers
|
|
50/push-EAX
|
|
# EAX = read-byte-buffered(f)
|
|
# . . push args
|
|
ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8)
|
|
# . . call
|
|
e8/call read-byte-buffered/disp32
|
|
# . . discard args
|
|
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP
|
|
# save EAX to Look
|
|
89/copy 0/mod/indirect 5/rm32/.disp32 . . 0/r32/EAX Look/disp32 . # copy EAX to *Look
|
|
$get-char:end:
|
|
# . restore registers
|
|
58/pop-to-EAX
|
|
# . epilog
|
|
89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP
|
|
5d/pop-to-EBP
|
|
c3/return
|
|
|
|
is-digit?: # c : int -> EAX : boolean
|
|
# . prolog
|
|
55/push-EBP
|
|
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
|
|
# EAX = false
|
|
b8/copy-to-EAX 0/imm32
|
|
# if (c < '0') return false
|
|
81 7/subop/compare 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 0x30/imm32 # compare *(EBP+8)
|
|
7c/jump-if-lesser $is-digit?:end/disp8
|
|
# if (c > '9') return false
|
|
81 7/subop/compare 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 0x39/imm32 # compare *(EBP+8)
|
|
7f/jump-if-greater $is-digit?:end/disp8
|
|
# otherwise return true
|
|
b8/copy-to-EAX 1/imm32
|
|
$is-digit?:end:
|
|
# . epilog
|
|
89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP
|
|
5d/pop-to-EBP
|
|
c3/return
|
|
|
|
== data
|
|
|
|
Look: # (char with some extra padding)
|
|
0/imm32
|
|
|
|
_test-output-stream:
|
|
# current write index
|
|
0/imm32
|
|
# current read index
|
|
0/imm32
|
|
# length
|
|
8/imm32
|
|
# data
|
|
00 00 00 00 00 00 00 00 # 8 bytes
|
|
|
|
_test-error-stream:
|
|
# current write index
|
|
0/imm32
|
|
# current read index
|
|
0/imm32
|
|
# length
|
|
0x40/imm32
|
|
# data (4 lines x 16 bytes/line)
|
|
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
|
|
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
|
|
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
|
|
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
|
|
|
|
# . . vim:nowrap:textwidth=0
|