fixed Constant Width
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ceriel
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2db075ab69
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287f8d5d70
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@ -158,13 +158,15 @@ One of the most fundamental operations in EM is ``loc c'', load the value of c
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on the stack. To expand this instruction the
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tables contain the following information:
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.DS
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EM_table : \fCW
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EM_table :
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.ft CW
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C_loc ==> "pushl $$$1".
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/* $1 refers to the first argument of C_loc.
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* $$ is a quoted $. */
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\fRas_table :\fCW
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\fRas_table :
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.ft CW
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pushl src : CONST ==>
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@text1( 0xd0);
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@text1( 0xef);
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@ -174,7 +176,7 @@ EM_table : \fCW
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.LP
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The as_table is transformed in the following routine:
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.DS
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\fCW
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.ft CW
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pushl_instr(src)
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t_operand *src;
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/* ``t_operand'' is a struct defined by the
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@ -189,7 +191,7 @@ t_operand *src;
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.DE
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Using ``pushl_instr()'', the following routine is generated from the EM_table:
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.DS
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\fCW
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.ft CW
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C_loc( c)
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arith c;
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/* text1() and text4() are library routines that fill the
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@ -335,7 +337,7 @@ the speed of the actual code expander. Finally, actions can be grouped into
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a list of actions; actions are separated by a semicolon and terminated
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by a ``.''.
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.DS
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\fCW
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.ft CW
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C_nop ==> .
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/* Empty action list : no operation. */
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@ -362,7 +364,7 @@ action list.
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.LP
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The following example illustrates the usage of labels.
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.DS
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\fCW
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.ft CW
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/* Compare the two top elements on the stack. */
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C_cmp ==> "pop bx";
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"pop cx";
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@ -397,7 +399,7 @@ The value of the $\fIi\fR argument referring to a parameter ($\fIi\fR >= 0)
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is increased by ``EM_BSIZE''. ``EM_BSIZE'' is the size of the return status block
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and must be defined in the file ``mach.h'' (see section 3.3). For example :
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.DS
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\fCW
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.ft CW
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C_lol ==> "push $1(bp)".
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/* automatic conversion of $1 */
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\fR
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@ -409,7 +411,7 @@ transformed into a unique assembly name. To prevent name clashes with library
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names the table writer has to provide the
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conversions in the file ``mach.h''. For example :
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.DS
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\fCW
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.ft CW
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C_bra ==> "jmp $1".
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/* automatic conversion of $1 */
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/* type arith is converted to string */
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@ -435,7 +437,7 @@ The boolean expressions in a COND_SEQUENCE must be C expressions. Besides the
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ordinary C operators and constants, $\fIi\fR references can be used
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in an expression.
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.DS
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\fCW
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.ft CW
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/* Load address of LB $1 levels back. */
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C_lxl
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$1 == 0 ==> "pushl fp".
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@ -454,7 +456,7 @@ these variants together. For this purpose the ``..'' notation is introduced.
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For the code expander there is no difference between the
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following instructions.
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.DS
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\fCW
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.ft CW
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C_loe_dlb ==> "pushl $1 + $2".
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C_loe_dnam ==> "pushl $1 + $2".
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C_loe ==> "pushl $1 + $2".
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@ -462,7 +464,7 @@ C_loe ==> "pushl $1 + $2".
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.DE
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So it can be written in the following way.
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.DS
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\fCW
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.ft CW
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C_loe.. ==> "pushl $1 + $2".
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\fR
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.DE
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@ -481,7 +483,7 @@ Most pseudo instructions are machine independent and are provided
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by \fBceg\fR. The table writer has only to supply the following functions,
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which are used to build a stackframe:
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.DS
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\fCW
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.ft CW
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C_prolog()
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/* Performs the prolog, for example save
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* return address */
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@ -512,7 +514,7 @@ C_rom_icon, C_con_icon, C_bss_icon, C_hol_icon can be abbreviated by ..icon.
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This also holds for ..ucon and ..fcon.
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For example :
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.DS
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\fCW
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.ft CW
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\\.\\.icon
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$2 == 1 ==> gen1( (ONE_BYTE) atoi( $1)).
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$2 == 2 ==> gen2( (TWO_BYTES) atoi( $1)).
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@ -630,7 +632,7 @@ There are three primitives that have to be defined by the table writer, either
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as functions in the file ``mach.c'' or as rules in the EM_table.
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For example, for the 8086 they look like this:
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.DS
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\fCW
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.ft CW
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C_jump ==> "jmp $1".
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C_prolog ==> "push bp";
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@ -781,7 +783,7 @@ right hand side gives the corresponding actions as \fBback\fR-primitives or as
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functions defined by the table writer, which call \fBback-primitives\fR.
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Two simple examples from the VAX as_table and the 8086 as_table, resp.:
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.DS
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\fCW
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.ft CW
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movl src, dst ==> @text1( 0xd0);
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gen_operand( src);
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gen_operand( dst).
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@ -822,7 +824,7 @@ that each mnemonic is mentioned only once in the as_table, otherwise
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.PP
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The following example shows the usage of type fields.
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.DS
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\fCW
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.ft CW
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mov dst:REG, src:EADDR ==>
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@text1( 0x8b); /* opcode */
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mod_RM( %d(dst->reg), src). /* operands */
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@ -832,8 +834,11 @@ The following example shows the usage of type fields.
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mod_RM( %d(src->reg), dst). /* operands */
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\fR
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.DE
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The table-writer must supply the restriction functions, \fCWREG\fR and
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\fCWEADDR\fR in the previous example, in ``as.c'' or ''as.h''.
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The table-writer must supply the restriction functions,
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.ft CW
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REG\fR and
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.ft CW
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EADDR\fR in the previous example, in ``as.c'' or ''as.h''.
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.NH 3
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The function of the @-sign and the if-statement.
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.PP
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@ -842,7 +847,9 @@ Since the as_table is
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interpreted on two levels, during code expander generation and during code
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expander execution, two levels of calls are present in it. A function-call
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without an ``@''-sign
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is called during code expander generation (e.g., the \fCWgen_operand()\fR in the
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is called during code expander generation (e.g., the
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.ft CW
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gen_operand()\fR in the
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first example).
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A function call with an ``@''-sign is called during code
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expander execution (e.g.,
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@ -854,7 +861,7 @@ can be replaced by ``move x, y'').
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In this case flags need to be set, unset, and tested during the execution of
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the compiler:
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.DS L
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\fCW
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.ft CW
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PUSH src ==> /* save in ax */
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mov_instr( AX_oper, src);
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/* set flag */
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@ -862,7 +869,7 @@ PUSH src ==> /* save in ax */
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\fR
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.DE
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.DS
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\fCW
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.ft CW
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POP dst ==> @if ( push_waiting)
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/* ``mov_instr'' is asg-generated */
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mov_instr( dst, AX_oper);
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@ -889,7 +896,7 @@ run time of the \fBce\fR. In such a condition one may of course refer
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to the ''$\fIi\fR'' arguments. For example, constants can be
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packed into one or two byte arguments as follows:
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.DS
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\fCW
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.ft CW
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mov dst:ACCU, src:DATA ==>
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@if ( fits_byte( %$(dst->expr)))
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@text1( 0xc0);
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@ -948,7 +955,7 @@ The following example illustrates the usage of ``%$''. (For an
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example that illustrates the usage of ordinary fields see
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the section on ``User supplied definitions and functions'').
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.DS
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\fCW
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.ft CW
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jmp dst ==>
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@text1( 0xe9);
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@reloc2( %$(dst->lab), %$(dst->off), PC_REL).
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@ -969,7 +976,7 @@ and reloc4()
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calls, saving space and time (no relocation at compiler run time).
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The following example illustrates the usage of ``%dist''.
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.DS
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\fCW
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.ft CW
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jmp dst:ILB ==> /* label in an instruction list */
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@text1( 0xeb);
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@text1( %dist( dst->lab)).
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@ -1012,7 +1019,7 @@ below).
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If the default assemble() does not work the way the table writer wants, he
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can supply his own version of it. Assemble() has the following arguments:
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.DS
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\fCW
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.ft CW
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assemble( instruction )
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char *instruction;
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\fR
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@ -1027,7 +1034,7 @@ required on a block of assembly instructions, the table writer only has to
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rewrite this function to get a new \fBceg\fR that obliges to his wishes.
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The function block_assemble has the following arguments:
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.DS
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\fCW
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.ft CW
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block_assemble( instructions, nr, first, last)
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char **instruction;
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int nr, first, last;
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@ -1053,7 +1060,7 @@ The following example shows the representative and essential parts of the
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.nr VS 12
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.LP
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.DS L
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\fCW
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.ft CW
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/* Constants and type definitions in as.h */
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#define UNKNOWN 0
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@ -1101,7 +1108,7 @@ extern struct t_operand saved_op, *AX_oper;
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.nr PS 10
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.nr VS 12
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.DS L
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\fCW
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.ft CW
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/* Some functions in as.c. */
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@ -1261,7 +1268,7 @@ for ``as_table'', ``as.h'', and ``as.c'' at this moment.
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.IP \0\03:
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type
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.br
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\fCW
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.ft CW
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install_ceg -as
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\fR
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.br
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@ -1272,7 +1279,9 @@ one for each
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EM-instruction. All these files will be compiled and put in a library called
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\fBce.a\fR.
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.br
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The option \fCW-as\fR means that a \fBback\fR-library will be
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The option
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.ft CW
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-as\fR means that a \fBback\fR-library will be
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generated (in the directory ``back'') that
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supports the generation of assembly language. The library is named ``back.a''.
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.IP \0\04:
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@ -1284,7 +1293,7 @@ tested (e.g., by running the compiler on the EM test set). If an error occurs,
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change the EM_table and type
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.IP
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.br
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\fCW
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.ft CW
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update_ceg\fR \fBC_instr
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\fR
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.br
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@ -1305,13 +1314,18 @@ Write the ``as_table'', ``as.h'', and ``as.c'' files.
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.IP \0\03:
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type
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.sp
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\fCW install_ceg -obj \fR
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.ft CW
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install_ceg -obj \fR
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.sp
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The option \fCW-obj\fR means that ``back.a'' will contain a library
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The option
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.ft CW
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-obj\fR means that ``back.a'' will contain a library
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for generating
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ACK.OUT(5ACK) object files, see appendix B.
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If the writer does not want to use the default ``back.a'',
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the \fCW-obj\fR flag must omitted and a ``back.a'' should be supplied that
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the
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.ft CW
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-obj\fR flag must omitted and a ``back.a'' should be supplied that
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generates the generates object code in the desired format.
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.IP \0\04:
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Link a front end, ``ce.a'', and ``back.a'' together resulting in a compiler
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@ -1322,12 +1336,14 @@ Then there are two ways to proceed:
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.IP \0\01:
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recompile the whole EM_table,
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.sp
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\fCW update_ceg ALL \fR
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.ft CW
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update_ceg ALL \fR
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.sp
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.IP \0\02:
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recompile just the few EM-instructions that contained the error,
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.sp
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\fCW update_ceg \fBC_instr\fR
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.ft CW
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update_ceg \fBC_instr\fR
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.sp
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where \fBC_instr\fR is an erroneous EM-instruction.
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This has to be done for every EM-instruction that contained the erroneous
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