INHALT

* NAME: LDR-APM DOC. 70180005000 REV. E PAGE 2

0024 * 0025 * PURPOSE 0026 * 0027 * LDR-APM LOADS FROM THE ASR, HIGH SPEED PAPER TAPE READER, 0028 * MAGNETIC TAPE, CARDS, AND DISC SERIES 16 ABSOLUTE AND RELOCATABLE 0029 * MAIN PROGRAMS AND SUBPROGRAMS PRODUCED BY THE ASSEMBLER AND 0030 * FORTRAN IV COMPILER. 0031 * 0032 * 0033 * STORAGE 0034 * 0035 * WHEN USING LDR-APM TO LOAD PAPER TAPE AND/OR DISC, 0036 * ONLY FOUR (4) CONSECUTIVE SECTORS ARE REQUIRED, WHEN USING 0037 * LDR-APM TO LOAD FROM MAGNETIC TAPE OR CARDS, FIVE (5) CONSECUTIVE 0038 * SECTORS ARE REQUIRED. 0039 * 0040 * 0041 * METHOD 0042 * 0043 * THE BINARY OUTPUT OF THE DAP-116 ASSEMBLER AND THE 0044 * FORTRAN IV COMPILER INCLUDES A 14-BIT ADDRESS FOR EACH 0045 * MEMORY REFERENCE. EACH INSTRUCTION IS CHECKED TO SEE IF ITS 0046 * REFERENCE IS IN THE SAME SECTOR AS THE INSTRUCTION. IF SO, 0047 * THE 14-BIT ADDRESS IS TRUNCATED TO 9 BITS AND THE SECTOR 0048 * BIT OF THE INSTRUCTION WORD IS SET TO 1. OTHERWISE AN 0049 * INDIRECT WORD IS MADE IN THE CROSS-SECTOR INDIRECT WORD 0050 * TABLE CONSISTING OF THE INSTRUCTION'S 14-BIT ADDRESS, TAG, 0051 * AND FLAG. THE INSTRUCTION IS LOADED WITH ITS INDIRECT FLAG 0052 * SET TO 1, ITS TAG AND ITS SECTOR BIT RESET TO O, AND ITS ADDRESS 0053 * SET TO THE LOCATION OF THE INDIRECT WORD. 0054 * 0055 * THE BINARY OUTPUT OF THE DAP-16 ASSEMBLER INCLUDES A 14- 0056 * BIT, 15-BIT OR 16-BIT ADDRESS FOR EACH MEMORY REFERENCE SO THAT 0057 * PROGRAMS MAY BE WRITTEN FOR COMPUTERS WITH THE EXTENDED 0058 * MEMORY OPTION. NINE-BIT ADDRESS INSTRUCTIONS ARE DESECTORED 0059 * BY THE LOADER EITHER FOR EXECUTION IN THE EXTENDED-MEMORY-MODE 0060 * (TAGS ARE NOT MOVED TO INDIRECT WORDS) OR FOR EXECUTION NOT IN 0061 * THE EXTENDED-MEMORY-MODE (TAGS ARE MOVED TO INDIRECT WORDS), 0062 * AS SELECTED BY THE PROGRAMMER AT ASSEMBLY TIME VIA THE PSEUDO- 0063 * OPERATIONS 'ENTER EXTEND-MODE DESECTORING' (EXD) AND 'LEAVE 0064 * EXTEND-MODE DESECTORING' (LXD). IT IS THE PROGRAMMER'S 0065 * RESPONSIBILITY TO DIRECT THAT CODE BE LOADED IN THE MODE IN 0066 * WHICH IS EXECUTED. THE DDP-516, H316 INSTRUCTION 'LOAD 0067 * INDEX' (LDX) IS AN EXCEPTION AND IS ALWAYS DESECTORED IN THE 0068 * EXTENDED-MEMORY-MODE (THE TAG IS NOT MOVED TO THE INDIRECT WORD). 0069 * 0070 * INDIRECT REFERENCE ACROSS SECTOR BUUNDARIES IS DONE 0071 * AUTOMATICALLY AND ONLY WHEN NEEDED. THIS LLOWS PROGRAMS WRITTEN 0072 * IN DAP-116 OR DAP-16 TO IGNORE THE SECTOR CONSTRAINTS ON 0073 * ADDRESSING. IN ADDITION, WITH THE EXTENDED MEMORY OPTION,