Section 0.4

Notation

In this section are given definitions of the symbols and abbreviations more commonly used in Orion programming documents. The following rules apply generally.

(a) Single capital letters often denote addresses of registers and the corresponding small letters the contents of these registers.

(b) A capital letter as a suffix implies that the suffixed symbol denotes the value of a word according to some convention (given below). A small letter as a suffix denotes that only a part of a word (i.e. a field) is to be considered.

Letters, possibly followed by numbers

A	Followed by a number - basic working-store address.
a	Suffix - “Argument” or Fixed-Point Part of a floating-point number (D0 to D39 of a word).
BS	The Backspace character
C	Followed by a number - character-number in a word (C0 to C7).
C( )	Content of the register or location whose address is in the parentheses.
c	Control number = address of current instruction.
c	Suffix - unsigned integer represented by the three most-significant bits of the word (D0, D1, D2).
CR	The Carriage Return character (5-track paper tape).
D	Followed by a number - digit-number in a word (D0 to D47).
d.l.	Double-length or double-precision
e	Suffix - exponent part of a floating-point number 128 less than the integer represented by digits D40 to D47 of the word.
ER	(or Er) The Erase character
F	Function of an instruction.
F	Suffix - value of a word interpreted as a fraction.
FS	The Figure Shift character (5-track paper tape).
G	Suffix - value of a word interpreted as a standard floating-point number.
I	Suffix - value of a word interpreted as an integer.
i	The number of a character within a word.
L	Suffix - logical quantity.
LC	The Lower Case character.
LF	The Line Feed character (5-track paper tape).
LS	The Letter Shift character (5-track paper tape).
l.s.	Less or least significant.
M	Mode of a peripheral transfer.
M	Suffix - value of two words representing a double-length mid-point number.
m	Suffix - modifier part of a word (digits D24 to D47).
m.s.	More or most significant.
NL	The Newline character.
OVR	The Overflow-indicator.
P	Followed by a number - pseudo-register address.
p	Followed by a number - content of specified pseudo-register.
PF	The Punch-Off character.
PN	The Punch-On character.
PT	The Paper Throw character.
pY	The content of pseudo-register Y
r	Suffix - the result of rounding the suffixed quantity.
s	Suffix - the sign-bit of the suffixed quantity.
s.l.	Single-length or single precision.
SP	(or Sp) The Space character
ST	The Stop character.
TB	The Tabulate character
u	Suffix - Upper half of a word (digits D0 to D23).
UC	The Upper Case character.
UL	The Underline character.
Ú	Or (logical operation).
VS	Visible Space (may be produced by SP or TB, or a combination of these possibly with BS).
X	The X-address in an instruction
x	The content of X
x	Suffix - the X-address part of a word (digits D9 to D23).
Y	The Y-address in an instruction
y	The content of Y
y	Suffix - the Y-address part of a word (digits D33 to D47).
Z	The Z-address in an instruction.
z	The content of Z

	Greek Letters
ε	2^-47
λ	The Letter Shift character in 5-track tape (also LS).
φ	The Figure Shift character in 5-track tape (also FS).

	Symbols
'	A prime or apostrophe indicates a value after an instruction has been obeyed.
( )	Sometimes used to denote the content.
&	And (logical operation).
≢	Not-equivalent (logical operation).
*	The quantity in the next register to that named.
:	The double-length quantity formed from the named quantity and that in the next register.
ā	A bar over any quantity indicates the logical "not" operation (also written ¬, for example ¬a).
=	Is equal to.
≠	Is not equal to.
>	Is greater than
¬>	Is not greater than.
≥	Is greater than or equal to.
<	Is less than
¬<	Is not less than
≤	Is less than or equal to.