PseudoSam Assembler Manual Level I Copyright(c) 1986,87,88 PseudoCorp All right reserved! Disclaimer: PseudoSam software is distributed as is, with no guarantee that it will work correctly in all situations. In no event will the Author be liable for any damages, including lost profits, lost savings or other incidental or consequential damages arising out of the use of or inability to use these programs, even if the Author has been advised of the possibility of such damages, or for any claim by any other party. It is the users reponsibility to back up all important files! See copyright information in appendix B Table of Contents Chapter 1 PseudoSam Assemblers vs. other assemblers. Chapter 2 Running the assembler program. Chapter 3 Assembler statement syntax. Chapter 4 Data types. Chapter 5 Expressions. Chapter 6 Assembler Directives. (also known as assembler pseudo-opcodes, or pseudo-ops) Appendix A ASCII character set. Appendix B Copyright information. Chapter 1 PseudoSam assemblers vs. other assemblers All PseudoSam(Pseudo brand Symbolic AsseMbler) assemblers conform to a common syntax based on the UNIX system V assembler syntax. By conforming to this Pseudo standard, conflicts with the manufacturers syntax are created. * The difference between another assembler's name and the PseudoSam name of an assembler directive can be circumvented by the .opdef directive. example .opdef eject,.eject ;defines eject to be synonymous with .eject .opdef fcc,.db ;fcc will now form constant characters as it ;should. * A file syn.asm is distributed with the assembler with some useful redefinitions. Unix system V is a trademark of AT & T. Chapter 2 Running the assembler program 1. Command line switch setting and source file specification. Assuming the user has an assembly language source file called foo.asm type the following command: aXX foo where the PseudoSam assembler number is substituted for XX. The assembler will assemble the program foo.asm using the default assembler switch settings. the following files will be generated by the assembler: foo.lst ;assembled listing shown the code conversion and ; any errors that where discover by the assembler. foo.obj ;assembled object code in Hex format. ** for a list of switch setting see the .command assembler directive description in chapter 6. *** The assembler uses the following temporary file names. z0z0z0z0.tmp z1z1z1z1.tmp ANY files with these names will be DESTROYED by the by the assembler. Chapter 3 Assembler statement syntax 1. Assembler Statements Assembler statements contain from zero to 4 fields as shown in following. <label> <opcode> <expressions> <comment> All fields are optional, but they must be in this order. A. Labels (<label>) are symbolic names that are assigned the starting address of any code generated by the opcode and or expressions of the line containing the label declaration.(see section 2). B. Operation codes(<opcode>) tell the assembler what machine instruction to generate, or what assembler control function to perform. The operation code also tells the assembler what expressions are required to complete the machine instruction or assembler directive. (see chapter 6). C. Expression requirements are set by the opcode(see the microprocessor manufacturers reference manual or the assembler directives chapter for individual opcode requirements).(see chapter 5). D. Comments are notes written by the programmer to explain what the program is trying to accomplish. Comments generate no code. (see section 3). 2. Labels Labels can be unlimited in length, but only the first eight characters are used to distinguish between them. They must conform to the following syntax. <label> -> <identifier>':' <identifier> -> <alphabetic character> <identifier character string> <alphabetic character> -> character in the set ['A'..'Z', 'a'..'z', '.'] <identifier character string> -> any sequence of characters from the set ['A'..'Z','a'..'z', '.', '0'..'9'] example abc: ;label referred to as abc a c: ;not a valid label foo: ;label referred to as foo .123: ;label referred to as .123 * Case makes NO difference! d: ;is the same as D: 3. Comments Comments must start with a semi-colon ; and are terminated by an end of line or file( <lf>(^J) or <sub>(^Z) ). An end of line is inserted by typing the enter or return key by most text editors. Chapter 4 Data types 1. Integers Integer constants can be specified in any of the following forms: A. Binary b'bb ;bb=string of binary digits B'bb B. Decimal ndd d'dd ;n=nozero decimal digit D'dd ;dd=string of decimal digits C. Octal 0qq ;qq=string of octal digits o'qq O'qq q'qq Q'qq D. Hexidecimal 0x'hh ;hh=string of hexidecimal digits 0X'hh h'hh H'hh x'hh X'hh Examples: 077 ;octal number 77 = decimal 63 b'0101 ;binary number 101 = decimal 5 77 ;decimal number 77 = octal 115 h'ff ;hexidecimal ff = decimal 255 2. Strings: Strings consist of a beginning quote " followed by any reasonable number of characters followed by an ending quote ". Control characters and double quotes " and backslash \ may not be used in strings directly. These special characters are included by using a special escape sequence which the assembler translates into the appropriate ASCII code. Note: Strings may not be used in expressions! Although character constants may(see below). Escape sequences "\"" string containing " "\\" string containing \ "\'" string containing ' "\0" string containing null "\n" string containing linefeed "\r" string containing carriage return "\f" string containing formfeed "\t" string containing horizontal tab "\nnn" string containing the ASCII character who's code is o'nnn (nnn are octal digits). * see appendix A for ASCII codes. 3. Character Constants: Character constants consist of a single quote ' followed by a character or an escape sequence(see above) followed by a single quote '. example: 'A' = ASCII character value for the letter A = 65 (decimal); '\''= ASCII character value for the character ' = 39 (decimal). Character constants are treated as integers by the assembler and are valid where ever an integer value is valid. example: 'A' + 1 = 66 * see appendix A for ASCII codes. 4. Symbolic values Symbolic values are generally labels, but may be any identifier assigned an integer value(using .set or .equ pseudo-ops). As a special case the symbol * when used as an operand in an expression denotes the value of the location counter (the value the program counter will have during operation) at the beginning of the current line. Chapter 5 Expressions All expressions evaluate to integer values modulo 65536(2^16) and are written in infix notation(the way you normally write them). Operators provided are grouped below in order of precedence. 1. (unary) ~ logical bit wise complement(not) of its operand(one's complement). - arithemetic complement, or negation(two's complement). 2. (binary) * integer multiply (two's complement). / integer divide (two's complement). % modulus (result is always positive) >> logical shift right (left operand shifted right operand times). << logical shift left (left operand shifted right operand times). ~ equivalent to A or ( ~B ). 3. (binary) | logical bitwise or(inclusive-or) of two operands. ^ logical bitwise exclusive-or of two operands. & logical bitwise and of two operands. 4. (binary) + addition (two's complement). - subtraction (two's complement). Since this version does not generate relocatable code there exists only one "type" of operand that can be in an expression. So anything goes except divide by 0(1 will be substituted ). examples: -1 = h'ffff (two's complement notation). -1 >> 8 = h'00ff -1 << 8 = h'ff00 3 / 2 = 1 6 / 2 = 3 5 / 0 = 5 -2 / 1 = -2 -3 /-2 = 1 2 * -3 = -6 b'00 & b'11 = 0 b'11 & b'10 = 2 2 * b'01 & b'10 = 2 b'01 ^ b'11 = 2 b'01 | b'11 = 3 Notice that spaces are ignored in expressions. Chapter 6 Assembler Directives (also known as assembler Pseudo-opcodes) The assembler recognizes the following directives: directive section...
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