Jump Over Left Menu
BAS Binary Card
An example of a BAS Binary Card is shown below:
Following the *BAS card will be one or more binary cards similar to this one. These cards all have punchings in rows 7 and 9 of column 1 and all but the last have additionally a punch in the + row of column 1. They will have been serially numbered in columns 79 and 80. Each binary card carries a checksum of all internal information. The use of this checksum may be suppressed by punching row 0 in column 1.
The binary cards contain information which can be loaded into any part of memory in such a way that the routine may operate there. The information found in rows 2 to 6 of column 1 is a binary count with the units position in row 6, and is a count of the number of words of information on the card. The other columns of binary cards are used as follows:
- Columns 2,3,4
- contains the relocation bits to indicate whether a particular 24 bit halfword is to be incremented by the value of the initial loading address of the routine. The punching is described below.
- Columns 5,6
- contain a 24 bit checksum of all the information on the card. The checksum is such that the logical sum (with end-around-carry) of the information in column 1 to 8 and of the information words contained in column 9 onwards is 77777777 octal
- Columns 7,8
- contains the loading address relative to the start of the routine of the first information word to be loaded.
- Column 9 onwards
- Each word of information occupies four columns, the first in column 9 to 12, the second in columns 13 to 16 and so on. From a group of columns the lower numbered columns represent the most significant binary digits of a word. Each word is treated for relocation as two separate 24 bit halfwords. The relocation bits in column 2 refer to the words contained in columns 9 to 32, the bits in column 3 to the words in columns 33 to 56 and those in column 4 to the words of columns 57 to 72. The relocation bits of a column are taken in turn from the + row down to the 9 row. A punch indicates that the 24 bit halfword is to be incremented by the initial loading address of the routine and the + row refers to the first pair of columns, the - row to the second and so on.
The information on the card shown can be decoded as follows:
- Column 1
- The columns punched are:
+ Not the last card 2 16 words on the card 7 BAS Card 9 BAS CardSo this is one card of a set for a subroutine and it is not the last and contains the full complement of 16 48-bit words.
- Relocation: Columns 2 to 4
- The punched holes indicate that:
Column 2 - Word 00 address is relocatable 3 Word 02 address is relocatable 7 Word 04 address is relocatable Column 3 - Word 06 address is relocatable 1 Word 07 address is relocatable 9 Word 13 address is relocatable Column 4 1 Word 15 address is relocatable 3 Word 16 address is relocatable
- Base Address of Card (Columns 7,8)
- these two columns indicate that the base address in octal is 0000304.0
- The Instructions
- The layout of the 4 columns is on the assumption that it is an instruction
so the shaded area is the first modifier and the next 7 bits is the second modifier.
The last two columns of the four give the address.
This gives the following instructions
00 0121 127 0 0000040.0 Transfer 01 0334 0 0 0000001.0 Load Acc 02 0330 0 0 0000436.0 Add 03 0356 0 0 0000001.0 Store Acc 04 0121 1 0 0000314.0 B1=204 05 0121 127 0 0000000.0 Transfer 06 00001140 6000026.0 07 2.0 10 0101 2 0 0000001.4 Load B2 11 0334 0 0 0000000.0 Load Acc 12 0356 0 2 0000117.0 Store Acc 13 0101 2 0 0000001.4 Load B2 14 0334 0 2 0000047.0 Load Acc 15 0356 0 0 0000003.0 Store 16 0101 2 0 0000003.4 Load B2 17 0334 0 2 0000156.0 Load AccInstructions 06 and 07 octal look as though they are data not instructions.
- Columns 73-80
- Gives the name of the routine as BOSS and it is the 13th card of the binary deck.