ftp.barnyard.co.uk/2015.02.ftp.barnyard.co.uk.tar/ftp.barnyard.co.uk/cpm/walnut-creek-CDROM/ZSYS/SIMTEL20/SYSLIB/SYSLIB.LBR/SYSLIBJ.HQP/SYSLIBJ.HLP

Text File | 2000-06-30 | 21KB | 633 lines

Branching 
Introduction
ACase     
Case via Reg A: ACASE1, ACASE2, ACASE3
HCase     
Case via Reg Pair HL: HCASE1, HCASE2, HCASE3
AGoto     
Computed GOTO via Reg A: AGOTO1, AGOTO2, BGOTO1, BGOTO2
HGoto     
Computed GOTO via RP HL: HGOTO1, HGOTO2, DGOTO1, DGOTO2
Aif       
Arithmetic IF via Reg A: AIF1, AIF2
Hif       
Arithmetic IF via RP HL: HIF1, HIF2
:Branching

     Thσ routine≤ iε thi≤ sectioε dea∞ witΦ conditiona∞ branchinτ ì
vißá CASE¼á ComputeΣá GOTO¼á anΣ Arithmetiπ I╞á constructs«á  Thσ ì
following example illustrates the case concept:

          < register A = key value >
               CALL ACASE1
               DB   SIZE      ; NUMBER OF ENTRIES IN TABLE
               DW   ERROR     ; GO HERE IF NO MATCH
               DB   VAL1      ; FIRST VALUE TO TEST FOR
               DW   ADDR1     ; GO HERE IF A = VAL1
               DB   VAL2      ; 2ND VALUE TO TEST FOR
               DW   ADDR2     ; GO HERE IF A = VAL2
               ...
               DB   VAL$SIZE  ; 'SIZE' VALUE TO TEST FOR
               DW   ADDR$SIZE ; GO HERE IF A = VAL$SIZE


     The following example illustrates the Computed GOTO:
          < register A = index (zero-relative) >
               CALL AGOTO1
               DW   ADDR0     ; GO HERE IF A = 0
               DW   ADDR1     ; GO HERE IF A = 1
               ...
               DW   ADDRN     ; GO HERE IF A = N

     Thσá followinτá examplσ illustrate≤ thσ ComputeΣá GOT╧á witΦ ì
limits:
          < register A = index (zero-relative) >
          < register B = limit >
               CALL AGOTO1
               DW   ADDR0     ; GO HERE IF A = 0
               DW   ADDR1     ; GO HERE IF A = 1
               ...
               DW   ADDRN     ; GO HERE IF A = N
          < error code >      ; RESUME AFTER DW ADDRN IF A > B

     The following example illustrates the Arithmetic IF:

          < register A = key value >
          < register B = test value >
               CALL AIF1
               DW   ADDRLT    ; GO HERE IF A < B
               DW   ADDREQ    ; GO HERE IF A = B
               DW   ADDRGT    ; GO HERE IF A > B

     Seσ thσ SYSLI┬ tes⌠ prograφ STEST014.MA├ fo≥ example≤ oµ usσ ì
of all of the branching routines.


     The following routines are provided:

     Routine   Comments
     =======   ========
     ACASE1    Case statement with A = key value
     ACASE2    Like ACASE1, but DE = address of case table
     ACASE3    Like ACASE2, but return address is left on stack

     HCASE▒    Likσ ACASE1¼ bu⌠ H╠ ╜ ke∙ value
     HCASE2    Like ACASE2, but HL = key value
     HCASE3    Like ACASE3, but HL = key value

     AGOTO1    Computed GOTO with A = key value
     AGOTO2    Like AGOTO1, but JMPs rather than DW follow

     HGOTO1    Computed GOTO with HL = key value
     HGOTO2    Like AGOTO2, but HL = key value


     Routine   Comments
     =======   ========
     BGOTO1    Like AGOTO1, but B = limit value
     BGOTO2    Like AGOTO2, but B = limit value

     DGOTO1    Like HGOTO1, but DE = limit value
     DGOTO2    Like HGOTO2, but DE = limit value

     AIF1      Arithmetic IF with A, B = values
     AIF2      Like AIF1, but JMPs rather than DW follow

     HIF1      Arithmetic IF with HL, DE = values
     HIF2      Like AIF2, but HL, DE = values

:ACASE Routines
     
Routine: ACASE1
     
Function║
     ACASE▒ i≤ ß casσ statemen⌠ processor«á  Oε input¼ registe≥ ┴ ì
contain≤ ß valuσ t∩ tes⌠ against«á  Thi≤ valuσ i≤ compareΣ t∩ thσ ì
value≤á iε ß casσ table¼á and¼á iµ ß matcΦ i≤ found¼á contro∞á i≤ ì
transferreΣá t∩á thσ addres≤ associateΣ witΦ thσ matchinτá value«  ì
Thi≤ casσ act≤ a≤ ß multiwa∙ JM╨ instructioε (returε addres≤ froφ ì
thσ cal∞ t∩ ACASE▒ i≤ no⌠ retained).

     
Example:
          MVI  A,TEST
          CALL ACASE1
          DB   N         ; number of entries in the table
          DW   DEFAULT   ; go to this address if no match
          DB   VAL1      ; test for TEST = VAL1
          DW   ADDR1     ; go here if TEST = VAL1
          ...
          DB   VALN      ; test for TEST = VALN
          DW   ADDRN     ; go here if TEST = VALN

     
Inputs: A = value to test for
     
Outputs: None (branch is made)

     
Registers Affected: None

     
SYSLIB Routines Called:   None
     
Special Error Conditions: None

     
Routine: ACASE2
     
Function║
     ACASE▓ i≤ ß casσ statemen⌠ processor«á  Oε input¼ registe≥ ┴ ì
contain≤á ß valuσ t∩ tes⌠ agains⌠ anΣ D┼ contain≤ thσ addres≤á oµ ì
thσá casσá table«á  Thσ valuσ iε registe≥ ┴ i≤á compareΣá t∩á thσ ì
value≤á iε ß casσ table¼á and¼á iµ ß matcΦ i≤ found¼á contro∞á i≤ ì
transferreΣá t∩á thσ addres≤ associateΣ witΦ thσ matchinτá value«  ì
Thi≤ casσ act≤ a≤ ß multiwa∙ JM╨ instructioε (returε addres≤ froφ ì
thσ cal∞ t∩ ACASE▓ i≤ no⌠ retained).


     
Example:
          MVI  A,TEST    ; value to test for
          LXI  D,TABLE   ; address of table
          CALL ACASE2
          ...
     TABLE:
          DB   N         ; number of entries in the table
          DW   DEFAULT   ; go to this address if no match
          DB   VAL1      ; test for TEST = VAL1
          DW   ADDR1     ; go here if TEST = VAL1
          ...
          DB   VALN      ; test for TEST = VALN
          DW   ADDRN     ; go here if TEST = VALN


     
Inputs: A = value to test for
               DE = address of case table
     
Outputs: None (branch is made)

     
Registers Affected: None

     
SYSLIB Routines Called:   None
     
Special Error Conditions: None

     
Routine: ACASE3
     
Function║
     ACASE│ i≤ ß casσ statemen⌠ processor«á  Oε input¼ registe≥ ┴ ì
contain≤á ß valuσ t∩ tes⌠ agains⌠ anΣ D┼ contain≤ thσ addres≤á oµ ì
thσá casσá table«á  Thσ valuσ iε registe≥ ┴ i≤á compareΣá t∩á thσ ì
value≤á iε ß casσ table¼á and¼á iµ ß matcΦ i≤ found¼á contro∞á i≤ ì
transferreΣá t∩á thσ addres≤ associateΣ witΦ thσ matchinτá value«  ì
Thi≤á casσá act≤ a≤ ß multiwa∙ CAL╠ instructioεá (returεá addres≤ ì
froφ thσ cal∞ t∩ ACASE│ i≤ lef⌠ oε thσ stack).


     
Example:
          MVI  A,TEST    ; value to test for
          LXI  D,TABLE   ; address of table
          CALL ACASE3
     < resume execution here if routines execute an RET instr >
          ...
     TABLE:
          DB   N         ; number of entries in the table
          DW   DEFAULT   ; go to this address if no match
          DB   VAL1      ; test for TEST = VAL1
          DW   ADDR1     ; go here if TEST = VAL1
          ...
          DB   VALN      ; test for TEST = VALN
          DW   ADDRN     ; go here if TEST = VALN


     
Inputs: A = value to test for
               DE = address of case table
     
Outputs: None (branch is made)

     
Registers Affected: None

     
SYSLIB Routines Called:   None
     
Special Error Conditions: None
:HCASE Routines
     
Routine: HCASE1
     
Function║
     HCASE▒ i≤ ß casσ statemen⌠ processor«á  Oεá input¼á registe≥ ì
pai≥ H╠ contain≤ ß valuσ t∩ tes⌠ against«  Thi≤ valuσ i≤ compareΣ ì
t∩ thσ value≤ iε ß casσ table¼á and¼ iµ ß matcΦ i≤ found¼ contro∞ ì
i≤ transferreΣ t∩ thσ addres≤ associateΣ witΦ thσ matchinτ value«  ì
Thi≤ casσ act≤ a≤ ß multiwa∙ JM╨ instructioε (returε addres≤ froφ ì
thσ cal∞ t∩ HCASE▒ i≤ no⌠ retained).

     
Example:
          LXI  H,TEST
          CALL HCASE1
          DW   N         ; number of entries in the table
          DW   DEFAULT   ; go to this address if no match
          DW   VAL1      ; test for TEST = VAL1
          DW   ADDR1     ; go here if TEST = VAL1
          ...
          DW   VALN      ; test for TEST = VALN
          DW   ADDRN     ; go here if TEST = VALN

     
Inputs: HL = value to test for
     
Outputs: None (branch is made)

     
Registers Affected: None

     
SYSLIB Routines Called:   None
     
Special Error Conditions: None

     
Routine: HCASE2
     
Function║
     HCASE▓á i≤ ß casσ statemen⌠ processor«á  Oε input¼á registe≥ ì
pai≥á H╠á contain≤ ß valuσ t∩ tes⌠ agains⌠ anΣá D┼á contain≤á thσ ì
addres≤á oµá thσ casσ table«á  Thσ valuσ iε registe≥ pai≥á H╠á i≤ ì
compareΣ t∩ thσ value≤ iε ß casσ table¼ and¼ iµ ß matcΦ i≤ found¼ ì
contro∞á i≤á transferreΣá t∩á thσá addres≤á associateΣá witΦá thσ ì
matchinτá value«á  Thi≤á casσ act≤ a≤ ß multiwa∙ JM╨á instructioε ì
(returε addres≤ froφ thσ cal∞ t∩ HCASE▓ i≤ no⌠ retained).


     
Example:
          LXI  H,TEST    ; value to test for
          LXI  D,TABLE   ; address of table
          CALL HCASE2
          ...
     TABLE:
          DW   N         ; number of entries in the table
          DW   DEFAULT   ; go to this address if no match
          DW   VAL1      ; test for TEST = VAL1
          DW   ADDR1     ; go here if TEST = VAL1
          ...
          DW   VALN      ; test for TEST = VALN
          DW   ADDRN     ; go here if TEST = VALN


     
Inputs: HL = value to test for
               DE = address of case table
     
Outputs: None (branch is made)

     
Registers Affected: None

     
SYSLIB Routines Called:   None
     
Special Error Conditions: None

     
Routine: HCASE3
     
Function║
     HCASE│ i≤ ß casσ statemen⌠ processor«á  Oεá input¼á registe≥ ì
pai≥á H╠á contain≤á ß valuσ t∩ tes⌠ agains⌠ anΣ D┼á contain≤á thσ ì
addres≤á oµá thσ casσ table«á  Thσ valuσ iε registe≥ pai≥á H╠á i≤ ì
compareΣ t∩ thσ value≤ iε ß casσ table¼ and¼ iµ ß matcΦ i≤ found¼ ì
contro∞á i≤á transferreΣá t∩á thσá addres≤á associateΣá witΦá thσ ì
matchinτá value«á  Thi≤ casσ act≤ a≤ ß multiwa∙ CAL╠á instructioε ì
(returε addres≤ froφ thσ cal∞ t∩ HCASE│ i≤ lef⌠ oε thσ stack).


     
Example:
          LXI  H,TEST    ; value to test for
          LXI  D,TABLE   ; address of table
          CALL HCASE3
     < resume execution here if routines execute an RET instr >
          ...
     TABLE:
          DW   N         ; number of entries in the table
          DW   DEFAULT   ; go to this address if no match
          DW   VAL1      ; test for TEST = VAL1
          DW   ADDR1     ; go here if TEST = VAL1
          ...
          DW   VALN      ; test for TEST = VALN
          DW   ADDRN     ; go here if TEST = VALN


     
Inputs: HL = value to test for
               DE = address of case table
     
Outputs: None (branch is made)

     
Registers Affected: None

     
SYSLIB Routines Called:   None
     
Special Error Conditions: None

:AGOTO (Computed Goto)

     
Routine: AGOTO1

     
Function║
     AGOTO▒ i≤ ß computeΣ GOTO«á  Wheε called¼ registe≥ ┴ ╜ inde° ì
(zero-relative⌐á oµá thσá followinτ addres≤á t∩á brancΦá to«á  N∩ ì
informatioε i≤ availablσ oε thσ numbe≥ oµ alloweΣ values¼á s∩á i⌠ ì
i≤á thσ programmer'≤ responsibilit∙ t∩ seσ tha⌠ thσ rangσ oµá thσ ì
Computed GOTO is not exceeded.

     
Example:
          MVI  A,INDEX   ; Index value
          CALL AGOTO1
          DW   ADDR0     ; GO HERE IF A = 0
          DW   ADDR1     ; GO HERE IF A = 1
          ...
          DW   ADDRN     ; GO HERE IF A = N


     
Inputs: A = index value (zero-relative)
     
Outputs: None

     
Registers Affected: None

     
SYSLIB Routines Called:   None
     
Special Error Conditions: None


     
Routine: AGOTO2

     
Function║
     AGOTO2 i≤ ß computeΣ GOTO«á  Wheε called¼ registe≥ ┴ ╜ inde° ì
(zero-relative⌐á oµá thσá followinτ addres≤á t∩á brancΦá to«á  N∩ ì
informatioε i≤ availablσ oε thσ numbe≥ oµ alloweΣ values¼á s∩á i⌠ ì
i≤á thσ programmer'≤ responsibilit∙ t∩ seσ tha⌠ thσ rangσ oµá thσ ì
Computed GOTO is not exceeded.

     
Example:
          MVI  A,INDEX   ; Index value
          CALL AGOTO2
          JMP  ADDR0     ; RETURN TO THIS JMP IF A = 0
          JMP  ADDR1     ; RETURN TO THIS JMP IF A = 1
          ...
          JMP  ADDRN     ; RETURN TO THIS JMP IF A = N
     < next instr >      ; RETURN TO THIS INSTR IF A = N+1


     
Inputs: A = index value (zero-relative)
     
Outputs: None

     
Registers Affected: None

     
SYSLIB Routines Called:   None
     
Special Error Conditions: None


     
Routine: BGOTO1

     
Function║
     BGOTO▒ i≤ ß computeΣ GOTO«á  Wheε called¼ registe≥ ┴ ╜ inde° ì
(zero-relative⌐ oµ thσ followinτ addres≤ t∩ brancΦ to«á  Registe≥ ì
┬ ╜ maximuφ valuσ alloweΣ fo≥ thσ inde° (registe≥ A)«á  Iµ ┴ ╛ B¼ ì
theεá contro∞á i≤ transferreΣ t∩ afte≥ thσ las⌠á addres≤á iεá thσ ì
table.

     
Example:
          MVI  A,INDEX   ; Index Value
          MVI  B,LIMIT   ; Maximum Index Value
          CALL BGOTO1
          DW   ADDR0     ; GO HERE IF A = 0
          DW   ADDR1     ; GO HERE IF A = 1
          ...
          DW   ADDR$LIMIT; GO HERE IF A = LIMIT
     < next instruction >; RETURN TO THIS INSTRUCTION IF A > LIMIT


     
Inputs: A = index value (zero-relative)
               B = maximum index value allowed
     
Outputs: None

     
Registers Affected: None

     
SYSLIB Routines Called:   None
     
Special Error Conditions: None


     
Routine: BGOTO2

     
Function║
     BGOTO▓ i≤ ß computeΣ GOTO«á  Wheε called¼ registe≥ ┴ ╜ inde° ì
(zero-relative⌐ oµ thσ followinτ addres≤ t∩ brancΦ to«á  Registe≥ ì
┬ ╜ maximuφ valuσ alloweΣ fo≥ thσ inde° (registe≥ A)«á  Iµ ┴ ╛ B¼ ì
theεá contro∞á i≤á transferreΣ t∩ afte≥ thσ las⌠ addres≤á iεá thσ ì
table.

     
Example:
          MVI  A,INDEX   ; Index value
          MVI  B,LIMIT   ; Maximum Index Value
          CALL BGOTO2
          JMP  ADDR0     ; RETURN TO THIS JMP IF A = 0
          JMP  ADDR1     ; RETURN TO THIS JMP IF A = 1
          ...
          JMP  ADDR$LIMIT; RETURN TO THIS JMP IF A = LIMIT
     < next instr >      ; RETURN TO THIS INSTR IF A > LIMIT


     
Inputs: A = index value (zero-relative)
               B = maximum index value
     
Outputs: None

     
Registers Affected: None

     
SYSLIB Routines Called:   None
     
Special Error Conditions: None

:HGOTO (Computed Goto)

     
Routine: HGOTO1

     
Function║
     HGOTO▒ i≤ ß computeΣ GOTO«á  Wheε called¼ registe≥ pai≥ H╠ ╜ ì
inde° (zero-relative⌐ oµ thσ followinτ addres≤ t∩ brancΦ to«á  N∩ ì
informatioε i≤ availablσ oε thσ numbe≥ oµ alloweΣ values¼á s∩á i⌠ ì
i≤á thσ programmer'≤ responsibilit∙ t∩ seσ tha⌠ thσ rangσ oµá thσ ì
ComputeΣ GOT╧ i≤ no⌠ exceeded.

     
Example:
          LXI  H,INDEX   ; Index value
          CALL HGOTO1
          DW   ADDR0     ; GO HERE IF HL = 0
          DW   ADDR1     ; GO HERE IF HL = 1
          ...
          DW   ADDRN     ; GO HERE IF HL = N


     
Inputs: HL = index value (zero-relative)
     
Outputs: None

     
Registers Affected: None

     
SYSLIB Routines Called:   None
     
Special Error Conditions: None


     
Routine: HGOTO2

     
Function║
     HGOTO▓ i≤ ß computeΣ GOTO«á  Wheε called¼ registe≥ pai≥ H╠ ╜ ì
inde° (zero-relative⌐ oµ thσ followinτ addres≤ t∩ brancΦ to«á  N∩ ì
informatioεá i≤ availablσ oε thσ numbe≥ oµ alloweΣ values¼á s∩ i⌠ ì
i≤á thσ programmer'≤ responsibilit∙ t∩ seσ tha⌠ thσ rangσ oµá thσ ì
ComputeΣ GOT╧ i≤ no⌠ exceeded.

     
Example:
          LXI  H,INDEX   ; Index value
          CALL HGOTO2
          JMP  ADDR0     ; RETURN TO THIS JMP IF HL = 0
          JMP  ADDR1     ; RETURN TO THIS JMP IF HL = 1
          ...
          JMP  ADDRN     ; RETURN TO THIS JMP IF HL = N
     < next instr >      ; RETURN TO THIS INSTR IF HL = N+1


     
Inputs: HL = index value (zero-relative)
     
Outputs: None

     
Registers Affected: None

     
SYSLIB Routines Called:   None
     
Special Error Conditions: None


     
Routine: DGOTO1

     
Function║
     DGOTO▒ i≤ ß computeΣ GOTO«á  Wheε called¼ registe≥ pai≥ H╠ ╜ ì
inde°á (zero-relative⌐á oµ thσ followinτ addres≤á t∩á brancΦá to«  ì
Registe≥á pai≥ D┼ ╜ maximuφ valuσ alloweΣ fo≥ thσ inde° (registe≥ ì
pai≥ HL)«á  Iµ H╠ ╛ DE¼á theε contro∞ i≤ transferreΣ t∩ afte≥ thσ ì
las⌠ addres≤ iε thσ table.

     
Example:
          LXI  H,INDEX   ; Index Value
          LXI  D,LIMIT   ; Maximum Index Value
          CALL DGOTO1
          DW   ADDR0     ; GO HERE IF HL = 0
          DW   ADDR1     ; GO HERE IF HL = 1
          ...
          DW   ADDR$LIMIT; GO HERE IF HL = LIMIT
     < next instruction >; RETURN TO THIS INSTRUCTION IF HL > LIMIT


     
Inputs: HL = index value (zero-relative)
               DE = maximum index value allowed
     
Outputs: None

     
Registers Affected: None

     
SYSLIB Routines Called:   None
     
Special Error Conditions: None


     
Routine: DGOTO2

     
Function║
     DGOTO▓ i≤ ß computeΣ GOTO«á  Wheε called¼ registe≥ pai≥ H╠ ╜ ì
inde°á (zero-relative⌐á oµ thσ followinτ addres≤á t∩á brancΦá to«  ì
Registe≥á pai≥ D┼ ╜ maximuφ valuσ alloweΣ fo≥ thσ inde° (registe≥ ì
pai≥ HL)«á  Iµ H╠ ╛ DE¼á theε contro∞ i≤ transferreΣ t∩ afte≥ thσ ì
las⌠ addres≤ iε thσ table.

     
Example:
          LXI  H,INDEX   ; Index value
          LXI  D,LIMIT   ; Maximum Index Value
          CALL DGOTO2
          JMP  ADDR0     ; RETURN TO THIS JMP IF HL = 0
          JMP  ADDR1     ; RETURN TO THIS JMP IF HL = 1
          ...
          JMP  ADDR$LIMIT; RETURN TO THIS JMP IF HL = LIMIT
     < next instr >      ; RETURN TO THIS INSTR IF HL > LIMIT


     
Inputs: HL = index value (zero-relative)
               DE = maximum index value
     
Outputs: None

     
Registers Affected: None

     
SYSLIB Routines Called:   None
     
Special Error Conditions: None

:AIF (Arithmetic IF with Register A)

     
Routine: AIF1

     
Function║
     AIF▒ i≤ aε arithmetiπ I╞ facility«  ┴ ke∙ valuσ i≤ passeΣ iε ì
thσá ┬á registe≥á anΣ ß tes⌠ valuσ i≤ passeΣ iε thσá ┴á register«  ì
Branchinτ i≤ donσ dependinτ oε thσ followinτ tests║ ┴ ╝ B¼ ┴ ╜ B¼ ì
and A > B.

     
Example:
          MVI  A,TEST    ; test value
          MVI  B,KEY     ; key value
          CALL AIF1
          DW   ALTB      ; GO HERE IF A < B
          DW   AEQB      ; GO HERE IF A = B
          DW   AGTB      ; GO HERE IF A > B


     
Inputs: A = test value
               B = key value
     
Outputs: None

     
Registers Affected: None

     
SYSLIB Routines Called: None
     
Special Error Conditions: None


     
Routine: AIF2

     
Function║
     AIF2 i≤ aε arithmetiπ I╞ facility«  ┴ ke∙ valuσ i≤ passeΣ iε ì
thσá ┬á registe≥á anΣ ß tes⌠ valuσ i≤ passeΣ iε thσá ┴á register«  ì
Branchinτ i≤ donσ dependinτ oε thσ followinτ tests║ ┴ ╝ B¼ ┴ ╜ B¼ ì
and A > B.

     
Example:
          MVI  A,TEST    ; test value
          MVI  B,KEY     ; key value
          CALL AIF2
          JMP  ALTB      ; RESUME AT THIS JMP IF A < B
          JMP  AEQB      ; RESUME AT THIS JMP IF A = B
          JMP  AGTB      ; RESUME AT THIS JMP IF A > B


     
Inputs: A = test value
               B = key value
     
Outputs: None

     
Registers Affected: None

     
SYSLIB Routines Called: None
     
Special Error Conditions: None

:HIF (Arithmetic IF with Register Pair HL)

     
Routine: HIF1

     
Function║
     HIF▒ i≤ aε arithmetiπ I╞ facility«  ┴ ke∙ valuσ i≤ passeΣ iε ì
thσá D┼á registe≥á pai≥á anΣ ß tes⌠ valuσ i≤á passeΣá iεá thσá H╠ ì
registe≥á pair«á  Branchinτá i≤ donσ dependinτ oεá thσá followinτ ì
tests║ H╠ ╝ DE¼ H╠ ╜ DE¼ anΣ H╠ ╛ DE.

     
Example:
          LXI  H,TEST    ; test value
          LXI  D,KEY     ; key value
          CALL HIF1
          DW   HLTD      ; GO HERE IF HL < DE
          DW   HEQD      ; GO HERE IF HL = DE
          DW   HGTD      ; GO HERE IF HL > DE


     
Inputs: HL = test value
               DE = key value
     
Outputs: None

     
Registers Affected: None

     
SYSLIB Routines Called: None
     
Special Error Conditions: None


     
Routine: HIF2

     
Function║
     HIF▓ i≤ aε arithmetiπ I╞ facility«  ┴ ke∙ valuσ i≤ passeΣ iε ì
thσá D┼á  registe≥á pai≥á anΣ ß tes⌠ valuσ i≤ passeΣá iεá thσá H╠ ì
registe≥á pair«á  Branchinτá i≤ donσ dependinτ oεá thσá followinτ ì
tests║ H╠ ╝ DE¼ H╠ ╜ DE¼ anΣ H╠ ╛ DE.

     
Example:
          LXI  H,TEST    ; test value
          LXI  D,KEY     ; key value
          CALL HIF2
          JMP  HLTD      ; RESUME AT THIS JMP IF HL < DE
          JMP  HEQD      ; RESUME AT THIS JMP IF HL = DE
          JMP  HGTD      ; RESUME AT THIS JMP IF HL > DE


     
Inputs: HL = test value
               DE = key value
     
Outputs: None

     
Registers Affected: None

     
SYSLIB Routines Called: None
     
Special Error Conditions: None