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The READ command allows for the reading of a DATA list and has an effect similar to a series of LET statements.
Each assignment within a single READ statement is dealt with in turn. The system variable X-PTR is used as a storage location for the pointer to the READ statement whilst CH-ADD is used to step along the DATA list.
READ_3 07660 RST 32 Come here on each pass, after the first, to move along the READ statement.
The address of this entry point is found in the parameter table.
READ 07661 CALL CLASS_01 Consider whether the variable has been used before; find the existing entry if it has.
07664 CALL SYNTAX_Z Jump forward if checking syntax.
07667 JR Z,READ_2
07669 RST 24 Save the current pointer CH-ADD in X-PTR.
07670 LD (23647),HL
07673 LD HL,(23639) Fetch the current DATA list pointer (DATADD) and jump forward unless a new DATA statement has to be found.
07676 LD A,(HL)
07677 CP ","
07679 JR Z,READ_1
07681 LD E,228 The search is for 'DATA'.
07683 CALL LOOK_PROG Jump forward if the search is successful.
07686 JR NC,READ_1
Report E - Out of DATA.
07688 RST 8 Call the error handling routine.
07689 DEFB 13
Continue - picking up a value from the DATA list.
READ_1 07690 CALL TEMP_PTR1 Advance the pointer along the DATA list and set CH-ADD.
07693 CALL VAL_FET_1 Fetch the value and assign it to the variable.
07696 RST 24 Fetch the current value of CH-ADD and store it in DATADD.
07697 LD (23639),HL
07700 LD HL,(23647) Fetch the pointer to the READ statement from X-PTR and clear it.
07703 LD (IY+38),0
07707 CALL TEMP_PTR2 Make CH-ADD once again point to the READ statement.
READ_2 07710 RST 24 Get the present character and see if it is a ','.
07711 CP ","
07713 JR Z,READ_3 If it is then jump back as there are further items; otherwise return via either CHECK_END (if checking syntax) or the 'RET' instruction (to STMT_RET).
07718 RET
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