Linker/exp.asm

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****************************************************************
*
* Expression evaluation
*
* This module handles evaluation of expressions during pass
* 2.
*
****************************************************************
copy directPage
****************************************************************
*
* ExpCommon - global data for the expression module
*
****************************************************************
*
;
; Constants
;
maxTerm gequ 16 max # of STACKED terms in an expression
maxDepth gequ 8 max # of NESTED unresolved labels
ExpCommon data
;
; External value returned by CopyExpression
;
copiedExpression ds 2 was the expression resolved to a constant?
shiftCount ds 4 shift count (# bits to shift)
shiftFlag ds 2 is the expression shifted?
shiftValue ds 4 expression value before shift
symbolCount ds 2 count attribute
symbolLength ds 2 length attribute
symbolRelocatable ds 2 symbol relocatable flag
symbolType ds 2 type attribute
symbolValue ds 4 symbol value
symbolData ds 2 symbol data area number
symbolFlag ds 2 symbol flags
symbolFile ds 2 symbol file
expSegment ds 2 segment number for the expression
;
; Current expression information
;
expValue ds 4 expression value
expLength ds 2 expression length
end
****************************************************************
*
* CopyExpression - resolve or copy an expression
*
* Inputs:
* ep - pointer to the first opcode in the expression
*
* Outputs:
* X-A constant value or ptr to a safe copy of the expression
* copiedExpression -
* 1 -> the value returned is a copy of the expression
* 0 -> the value returned is a constant
*
****************************************************************
*
CopyExpression start
using ExpCommon
val equ 1 value of the expression
oep equ 5 original copy of ep
length equ 9 length of the expression, in bytes
done equ 13 done processing flag
sp equ 15 expression stack pointer
stack equ 17 expression stack
sub (4:ep),16+maxTerm*4
stz copiedExpression assume we can resolve to a constant
move4 ep,oep save a copy of the start of the expression
stz done not done, yet
stz sp nothing on the operand stack
lb1 lda [ep] loop over the expression, processing it
and #$00FF
asl A
tax
jsr (addr,X)
lda done
beq lb1
lda #9 if sp <> 4 then
ldx sp
cpx #4
jne TermError flag an expression syntax error
move4 stack,val set the value
lda copiedExpression if the expression is not constant then
beq lb4
sub2 ep,oep,length get some memory from the symbol table
ph2 length
jsr GetSymbolMemory
sta val
stx val+2
sta ep
stx ep+2
lda length X = # of words to copy
lsr A
tax
bcc lb2 if there are an odd # of bytes then
short M
lda [oep]
sta [ep]
long M
inc4 oep
inc4 ep
tax
beq lb4
lb2 ldy #0
lb3 lda [oep],Y
sta [ep],Y
iny
iny
dex
bne lb3
lb4 ret 4:val return the expression value
;
; Add:
;
Add anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
clc do the operation
lda stack-4,X
adc stack,X
sta stack-4,X
lda stack-2,X
adc stack+2,X
sta stack-2,X
rts
;
; And:
;
And anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-4,X do the operation
ora stack-2,X
beq and1
lda stack,X
ora stack+2,X
beq and1
lda #1 result is true
bra and2
and1 lda #0 result is false
and2 sta stack-4,X
lda #0
sta stack-2,X
rts
;
; BAnd:
;
BAnd anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-4,X do the operation
and stack,X
sta stack-4,X
lda stack-2,X
and stack+2,X
sta stack-2,X
rts
;
; BEor:
;
BEor anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-4,X do the operation
eor stack,X
sta stack-4,X
lda stack-2,X
eor stack+2,X
sta stack-2,X
rts
;
; BNot:
;
BNot anop
inc4 ep update ep
jsr Check1 make sure there is at least 1 operand
lda stack-4,X do the operation
eor #$FFFF
sta stack-4,X
lda stack-2,X
eor #$FFFF
sta stack-2,X
rts
;
; BOr:
;
BOr anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-4,X do the operation
ora stack,X
sta stack-4,X
lda stack-2,X
ora stack+2,X
sta stack-2,X
rts
;
; Check1 - Makes sure there is at least 1 operand. Returns sp in X.
;
Check1 anop
ldx sp
beq check2a
rts
;
; Check2 - Makes sure there are at least 2 operands. Removes 1, returns
; new sp in X.
;
Check2 anop
lda sp
cmp #8
bge check21
check2a lda #9
jmp TermError
check21 sec
sbc #4
sta sp
tax
rts
;
; CheckStack - check for stack overflows
;
CheckStack anop
lda #9
ldx sp
cpx #maxTerm*4
jeq TermError
rts
;
; Div:
;
Div anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-2,X do the operation
pha
lda stack-4,X
pha
lda stack+2,X
pha
lda stack,X
pha
jsl ~Div4
ldx sp
pla
sta stack-4,X
pla
sta stack-2,X
pla
pla
rts
;
; Eor:
;
Eor anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-4,X do the operation
ora stack-2,X
bne eor1
lda stack,X
ora stack+2,X
bne eor2
bra eor3
eor1 lda stack,X
ora stack+2,X
bne eor3
eor2 lda #1 result is true
bra eor4
eor3 lda #0 result is false
eor4 sta stack-4,X
lda #0
sta stack-2,X
rts
;
; EndExp - end of the expression
;
EndExp anop
inc4 ep
inc done
rts
;
; EQ:
;
EQ anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-4,X do the operation
cmp stack,X
bne eq1
lda stack-2,X
cmp stack+2,X
bne eq1
lda #1 result is true
bra eq2
eq1 lda #0 result is false
eq2 ldx sp
sta stack-4,X
lda #0
sta stack-2,X
rts
;
; Invalid - illegal byte in the expression
;
Invalid anop
lda #8
jmp TermError
;
; LE:
;
LE anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-2,X do the operation
pha
lda stack-4,X
pha
lda stack+2,X
pha
lda stack,X
pha
jsl SCmp4
ble le1
lda #0 result is false
bra le2
le1 lda #1 result is true
le2 ldx sp
sta stack-4,X
lda #0
sta stack-2,X
rts
;
; LT:
;
LT anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-2,X do the operation
pha
lda stack-4,X
pha
lda stack+2,X
pha
lda stack,X
pha
jsl SCmp4
blt lt1
lda #0 result is false
bra lt2
lt1 lda #1 result is true
lt2 ldx sp
sta stack-4,X
lda #0
sta stack-2,X
rts
;
; GE:
;
GE anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-2,X do the operation
pha
lda stack-4,X
pha
lda stack+2,X
pha
lda stack,X
pha
jsl SCmp4
bge ge1
lda #0 result is false
bra ge2
ge1 lda #1 result is true
ge2 ldx sp
sta stack-4,X
lda #0
sta stack-2,X
rts
;
; GT:
;
GT anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-2,X do the operation
pha
lda stack-4,X
pha
lda stack+2,X
pha
lda stack,X
pha
jsl SCmp4
bgt gt1
lda #0 result is false
bra gt2
gt1 lda #1 result is true
gt2 ldx sp
sta stack-4,X
lda #0
sta stack-2,X
rts
;
; Mod:
;
Mod anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-2,X do the operation
pha
lda stack-4,X
pha
lda stack+2,X
pha
lda stack,X
pha
jsl ~Div4
pla
pla
ldx sp
pla
sta stack-4,X
pla
sta stack-2,X
rts
;
; Mul:
;
Mul anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-2,X do the operation
pha
lda stack-4,X
pha
lda stack+2,X
pha
lda stack,X
pha
jsl ~Mul4
ldx sp
pla
sta stack-4,X
pla
sta stack-2,X
rts
;
; NE:
;
NE anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-4,X do the operation
cmp stack,X
bne ne1
lda stack-2,X
cmp stack+2,X
bne ne1
lda #0 result is false
bra ne2
ne1 lda #1 result is true
ne2 ldx sp
sta stack-4,X
lda #0
sta stack-2,X
rts
;
; Not:
;
Not anop
inc4 ep update ep
jsr Check1 make sure there are at least 2 operands
lda stack-4,X do the operation
ora stack-2,X
bne not1
lda #1 result is true
bra not2
not1 lda #0 result is false
not2 sta stack-4,X
lda #0
sta stack-2,X
rts
;
; Or:
;
Or anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-4,X do the operation
ora stack-2,X
bne or1
lda stack,X
ora stack+2,X
bne or1
lda #0 result is false
bra or2
or1 lda #1 result is true
or2 sta stack-4,X
lda #0
sta stack-2,X
rts
;
; PCounter - program counter
;
PCounter anop
lda #1 copiedExpression = true
sta copiedExpression
inc4 ep skip the op code
jsr CheckStack make sure there is room on the stack
add2 sp,#4 reserve space on the operand stack
rts
;
; Reference - a reference to a label
;
Reference anop
lda #1 copiedExpression = true
sta copiedExpression
jsr CheckStack make sure there is room on the stack
add2 sp,#4 reserve space on the operand stack
inc4 ep skip the op code
lda [ep] skip the name in the segment
and #$00FF
sec
adc ep
sta ep
bcc rf1
inc ep+2
rf1 rts
;
; SegDisp - disp from the start of the segment
;
SegDisp anop
lda #1 copiedExpression = true
sta copiedExpression
jsr CheckStack make sure there is room on the stack
add4 ep,#5 skip the op code and operand
add2 sp,#4 reserve space on the operand stack
rts
;
; Shift:
;
Shift anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack+2,X if shift is to the right then
bpl shift2
lda stack,X shift to the right
tay
shift1 lsr stack-2,X
ror stack-4,X
iny
bne shift1
rts return
shift2 lda stack,X shift to the left
tay
beq shift4
shift3 asl stack-4,X
rol stack-2,X
dey
bne shift3
shift4 rts
;
; Sub:
;
Sub anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
sec do the operation
lda stack-4,X
sbc stack,X
sta stack-4,X
lda stack-2,X
sbc stack+2,X
sta stack-2,X
rts
;
; UMinus:
;
UMinus anop
inc4 ep update ep
jsr Check1 make sure there is at least 1 operand
sec do the operation
lda #0
sbc stack-4,X
sta stack-4,X
lda #0
sbc stack-2,X
sta stack-2,X
rts
;
; Value - constant value
;
Value anop
jsr CheckStack make sure there is room on the stack
ldy #1 place the value on the stack
ldx sp
lda [ep],Y
sta stack,X
ldy #3
lda [ep],Y
sta stack+2,X
add4 ep,#5 skip the op code and operand
add2 sp,#4 reserve space on the operand stack
rts
;
; Table of expression handling subroutines
;
addr dc a'EndExp' $00 End
dc a'Add' $01 +
dc a'Sub' $02 -
dc a'Mul' $03 *
dc a'Div' $04 div
dc a'Mod' $05 mod
dc a'UMinus' $06 unary -
dc a'Shift' $07 << or >>
dc a'And' $08 and
dc a'Or' $09 or
dc a'Eor' $0A eor
dc a'Not' $0B not
dc a'LE' $0C <=
dc a'GE' $0D >=
dc a'NE' $0E <>
dc a'LT' $0F <
dc a'GT' $10 >
dc a'EQ' $11 =
dc a'BAnd' $12 &
dc a'BOr' $13 |
dc a'BEor' $14 bitwise eor
dc a'BNot' $15 bitwise not
dc 10a'Invalid' $16..$1F unused
dc 16a'Invalid' $20..$2F unused
dc 16a'Invalid' $30..$3F unused
dc 16a'Invalid' $40..$4F unused
dc 16a'Invalid' $50..$5F unused
dc 16a'Invalid' $60..$6F unused
dc 16a'Invalid' $70..$7F unused
dc a'PCounter' $80 program counter
dc a'Value' $81 absolute value
dc a'Reference' $82 weak label reference
dc a'Reference' $83 strong label reference
dc a'Reference' $84 length attribute
dc a'Reference' $85 type attribute
dc a'Reference' $86 count attribute
dc a'SegDisp' $87 disp from start of segment
dc 8a'Invalid' $88-8F unused
dc 16a'Invalid' $90..$9F unused
dc 16a'Invalid' $A0..$AF unused
dc 16a'Invalid' $B0..$BF unused
dc 16a'Invalid' $C0..$CF unused
dc 16a'Invalid' $D0..$DF unused
dc 16a'Invalid' $E0..$EF unused
dc 16a'Invalid' $F0..$FF unused
end
****************************************************************
*
* Evaluate - evaluate an expression
*
* Inputs:
* ep - pointer to the expression
*
* Outputs:
* shiftFlag - 1 if the value is shifted, else 0
* shiftValue - expression result before shifting
* shiftCount - shift counter
* symbolRelocatable - non-zero if sym is relocatable
* returns the value of the expression
*
****************************************************************
*
Evaluate start
using Common
using ExpCommon
done equ 1 done processing flag
sp equ 3 expression stack pointer
stack equ 7 expression stack
sub (4:ep),6+maxTerm*5
tsc check for a stack overflow
sec
sbc #$0100
cmp dpReg
bge lb0
lda #9
jmp TermError
lb0 stz shiftFlag no shift has occurred
stz shiftCount
stz shiftCount+2
stz done not done, yet
stz sp nothing on the operand stack
stz expSegment no segment-dependent variables, yet
lb1 lda [ep] loop over the expression, processing it
and #$00FF
asl A
tax
jsr (addr,X)
lda done
beq lb1
lda #9 if sp <> 4 then
ldx sp
cpx #5
jne TermError flag an expression syntax error
lda stack+4 set the relocatable flag
and #$00FF
sta symbolRelocatable
ret 4:stack return the expression value
;
; Add:
;
Add anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
clc do the operation
lda stack-5,X
adc stack,X
sta stack-5,X
lda stack-3,X
adc stack+2,X
sta stack-3,X
lda stack-1,X if both operands are relative then
and stack+4,X
and #$00FF
beq ad1
ph4 #0 Error(NULL,16)
ph2 #16
jsr Error
rts
ad1 lda stack-1,X if either operand is relative and a
ora stack+4,X shift has occurred then
and #$00FF
beq ad3
lda shiftFlag
beq ad2
ph4 #0 Error(NULL,16)
ph2 #16
jsr Error
rts
ad2 lda #1 one operand is relative, so the result
sta stack-1,X is also relative
ad3 rts
;
; And:
;
And anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-5,X do the operation
ora stack-3,X
beq and1
lda stack,X
ora stack+2,X
beq and1
lda #1 result is true
bra and2
and1 lda #0 result is false
and2 sta stack-5,X
lda #0
sta stack-3,X
jsr NoRelocate2 make sure the operands are not relocatable
rts
;
; AttrCount - get the count attribute of a label
;
AttrCount anop
inc4 ep skip the op code
ph4 ep find the symbol value
ph2 #0
jsr GetSymbolValue
jsr CheckStack make sure there is room on the stack
lda symbolCount save the value
sta stack,X
lda #0
sta stack+2,X
short M set the relocation flag
lda #0
sta stack+4,X
long M
add2 sp,#5 reserve space on the operand stack
lda [ep] skip the name in the segment
and #$00FF
sec
adc ep
sta ep
bcc ac1
inc ep+2
ac1 rts
;
; AttrLength - get the length attribute of a label
;
AttrLength anop
inc4 ep skip the op code
ph4 ep find the symbol value
ph2 #1
jsr GetSymbolValue
jsr CheckStack make sure there is room on the stack
lda symbolLength save the value
sta stack,X
lda #0
sta stack+2,X
short M set the relocation flag
lda #0
sta stack+4,X
long M
add2 sp,#5 reserve space on the operand stack
lda [ep] skip the name in the segment
and #$00FF
sec
adc ep
sta ep
bcc al1
inc ep+2
al1 rts
;
; AttrType - get the type attribute of a label
;
AttrType anop
inc4 ep skip the op code
ph4 ep find the symbol value
ph2 #1
jsr GetSymbolValue
jsr CheckStack make sure there is room on the stack
lda symbolType save the value
sta stack,X
lda #0
sta stack+2,X
short M set the relocation flag
lda #0
sta stack+4,X
long M
add2 sp,#5 reserve space on the operand stack
lda [ep] skip the name in the segment
and #$00FF
sec
adc ep
sta ep
bcc at1
inc ep+2
at1 rts
;
; BAnd:
;
BAnd anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-5,X do the operation
and stack,X
sta stack-5,X
lda stack-3,X
and stack+2,X
sta stack-3,X
jsr NoRelocate2 make sure the operands are not relocatable
rts
;
; BEor:
;
BEor anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-5,X do the operation
eor stack,X
sta stack-5,X
lda stack-3,X
eor stack+2,X
sta stack-3,X
jsr NoRelocate2 make sure the operands are not relocatable
rts
;
; BNot:
;
BNot anop
inc4 ep update ep
jsr Check1 make sure there is at least 1 operand
lda stack-5,X do the operation
eor #$FFFF
sta stack-5,X
lda stack-3,X
eor #$FFFF
sta stack-3,X
jsr NoRelocate1 make sure the operand is not relocatable
rts
;
; BOr:
;
BOr anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-5,X do the operation
ora stack,X
sta stack-5,X
lda stack-3,X
ora stack+2,X
sta stack-3,X
jsr NoRelocate2 make sure the operands are not relocatable
rts
;
; Check1 - Makes sure there is at least 1 operand. Returns sp in X.
;
Check1 anop
ldx sp
beq check2a
rts
;
; Check2 - Makes sure there are at least 2 operands. Removes 1, returns
; new sp in X.
;
Check2 anop
lda sp
cmp #10
bge check21
check2a lda #9
jmp TermError
check21 sec
sbc #5
sta sp
tax
rts
;
; CheckStack - check for stack overflows
;
CheckStack anop
lda #9
ldx sp
cpx #maxTerm*5
jeq TermError
rts
;
; Div:
;
Div anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-3,X do the operation
pha
lda stack-5,X
pha
lda stack+2,X
pha
lda stack,X
pha
jsl ~Div4
ldx sp
pla
sta stack-5,X
pla
sta stack-3,X
pla
pla
jsr NoRelocate2 make sure the operands are not relocatable
rts
;
; Eor:
;
Eor anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-5,X do the operation
ora stack-3,X
bne eor1
lda stack,X
ora stack+2,X
bne eor2
bra eor3
eor1 lda stack,X
ora stack+2,X
bne eor3
eor2 lda #1 result is true
bra eor4
eor3 lda #0 result is false
eor4 sta stack-5,X
lda #0
sta stack-3,X
jsr NoRelocate2 make sure the operands are not relocatable
rts
;
; EndExp - end of the expression
;
EndExp anop
inc4 ep
inc done
rts
;
; EQ:
;
EQ anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-5,X do the operation
cmp stack,X
bne eq1
lda stack-3,X
cmp stack+2,X
bne eq1
lda #1 result is true
bra eq2
eq1 lda #0 result is false
eq2 ldx sp
sta stack-5,X
lda #0
sta stack-3,X
jsr NoRelocate2 make sure the operands are not relocatable
rts
;
; Invalid - illegal byte in the expression
;
Invalid anop
lda #8
jmp TermError
;
; LE:
;
LE anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-3,X do the operation
pha
lda stack-5,X
pha
lda stack+2,X
pha
lda stack,X
pha
jsl SCmp4
ble le1
lda #0 result is false
bra le2
le1 lda #1 result is true
le2 ldx sp
sta stack-5,X
lda #0
sta stack-3,X
jsr NoRelocate2 make sure the operands are not relocatable
rts
;
; LT:
;
LT anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-3,X do the operation
pha
lda stack-5,X
pha
lda stack+2,X
pha
lda stack,X
pha
jsl SCmp4
blt lt1
lda #0 result is false
bra lt2
lt1 lda #1 result is true
lt2 ldx sp
sta stack-5,X
lda #0
sta stack-3,X
jsr NoRelocate2 make sure the operands are not relocatable
rts
;
; GE:
;
GE anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-3,X do the operation
pha
lda stack-5,X
pha
lda stack+2,X
pha
lda stack,X
pha
jsl SCmp4
bge ge1
lda #0 result is false
bra ge2
ge1 lda #1 result is true
ge2 ldx sp
sta stack-5,X
lda #0
sta stack-3,X
jsr NoRelocate2 make sure the operands are not relocatable
rts
;
; GT:
;
GT anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-3,X do the operation
pha
lda stack-5,X
pha
lda stack+2,X
pha
lda stack,X
pha
jsl SCmp4
bgt gt1
lda #0 result is false
bra gt2
gt1 lda #1 result is true
gt2 ldx sp
sta stack-5,X
lda #0
sta stack-3,X
jsr NoRelocate2 make sure the operands are not relocatable
rts
;
; Mod:
;
Mod anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-3,X do the operation
pha
lda stack-5,X
pha
lda stack+2,X
pha
lda stack,X
pha
jsl ~Div4
pla
pla
ldx sp
pla
sta stack-5,X
pla
sta stack-3,X
jsr NoRelocate2 make sure the operands are not relocatable
rts
;
; Mul:
;
Mul anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-3,X do the operation
pha
lda stack-5,X
pha
lda stack+2,X
pha
lda stack,X
pha
jsl ~Mul4
ldx sp
pla
sta stack-5,X
pla
sta stack-3,X
jsr NoRelocate2 make sure the operands are not relocatable
rts
;
; NE:
;
NE anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-5,X do the operation
cmp stack,X
bne ne1
lda stack-3,X
cmp stack+2,X
bne ne1
lda #0 result is false
bra ne2
ne1 lda #1 result is true
ne2 ldx sp
sta stack-5,X
lda #0
sta stack-3,X
jsr NoRelocate2 make sure the operands are not relocatable
rts
;
; NoRelocate1 - make sure the top operand is not relocatable
;
NoRelocate1 anop
lda stack-1,X
bra nr0
;
; NoRelocate2 - make sure the top two operands are not relocatable
;
NoRelocate2 anop
lda stack-1,X
ora stack+4,X
nr0 and #$00FF
beq nr1
ph4 #0
ph2 #16
jsr Error
nr1 rts
;
; Not:
;
Not anop
inc4 ep update ep
jsr Check1 make sure there are at least 2 operands
lda stack-5,X do the operation
ora stack-3,X
bne not1
lda #1 result is true
bra not2
not1 lda #0 result is false
not2 sta stack-5,X
lda #0
sta stack-3,X
jsr NoRelocate1 make sure the operand is not relocatable
rts
;
; Or:
;
Or anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda stack-5,X do the operation
ora stack-3,X
bne or1
lda stack,X
ora stack+2,X
bne or1
lda #0 result is false
bra or2
or1 lda #1 result is true
or2 sta stack-5,X
lda #0
sta stack-3,X
jsr NoRelocate2 make sure the operands are not relocatable
rts
;
; PCounter - program counter
;
PCounter anop
inc4 ep skip the op code
ldx dpReg get the program counter
lda >pc+2,X
pha
lda >pc,X
pha
jsr CheckStack make sure there is room on the stack
pla save the program counter
sta stack,X
pla
sta stack+2,X
short M value is relocatable
lda #1
sta stack+4,X
long M
add2 sp,#5 reserve space on the operand stack
rts
;
; Reference - a reference to a label
;
Reference anop
inc4 ep skip the op code
ph4 ep find the symbol value
ph2 #1
jsr GetSymbolValue
jsr CheckStack make sure there is room on the stack
lda symbolValue save the value
sta stack,X
lda symbolValue+2
sta stack+2,X
short M set the relocation flag
lda symbolRelocatable
sta stack+4,X
long M
add2 sp,#5 reserve space on the operand stack
lda [ep] skip the name in the segment
and #$00FF
sec
adc ep
sta ep
bcc rf1
inc ep+2
rf1 rts
;
; SegDisp - disp from the start of the segment
;
SegDisp anop
jsr CheckStack make sure there is room on the stack
clc save the value + startpc
lda startpc
ldy #1
adc [ep],Y
sta stack,X
lda startpc+2
iny
iny
adc [ep],Y
sta stack+2,X
short M value is relocatable
lda #1
sta stack+4,X
long M
add4 ep,#5 skip the op code and operand
add2 sp,#5 reserve space on the operand stack
rts
;
; Shift:
;
Shift anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
lda shiftFlag a shift can only be done 1 time
beq shift0
phx
ph4 #0
ph2 #2
jsr Error
plx
stz shiftFlag
shift0 inc shiftFlag
lda stack,X save the shift count
sta shiftCount
lda stack+2,X
sta shiftCount+2
bmi sh2 restrict it to a reasonable range
bne sh1
lda shiftCount
cmp #32
blt sh4
sh1 lla shiftCount,32
bra sh4
sh2 inc A
bne sh3
lda shiftCount
cmp #-32
bge sh4
sh3 lla shiftCount,-32
sh4 lda stack-5,X save the shifted value
sta shiftValue
lda stack-3,X
sta shiftValue+2
lda stack+2,X if shift is to the right then
bpl shift2
lda stack,X shift to the right
tay
shift1 lsr stack-3,X
ror stack-5,X
iny
bne shift1
rts return
shift2 lda stack,X shift to the left
tay
beq shift4
shift3 asl stack-5,X
rol stack-3,X
dey
bne shift3
shift4 rts
;
; Sub:
;
Sub anop
inc4 ep update ep
jsr Check2 make sure there are at least 2 operands
sec do the operation
lda stack-5,X
sbc stack,X
sta stack-5,X
lda stack-3,X
sbc stack+2,X
sta stack-3,X
lda stack-1,X if both operands are relative then
and stack+4,X
and #$00FF
beq su1
lda #0 result is a constant
sta stack-1,X
rts
su1 lda stack-1,X if either operand is relative and a
ora stack+4,X shift has occurred then
and #$00FF
beq su3
lda shiftFlag
beq su2
ph4 #0 Error(NULL,16)
ph2 #16
jsr Error
rts
su2 lda #1 one operand is relative, so the result
sta stack-1,X is also relative
su3 rts
;
; UMinus:
;
UMinus anop
inc4 ep update ep
jsr Check1 make sure there is at least 1 operand
sec do the operation
lda #0
sbc stack-5,X
sta stack-5,X
lda #0
sbc stack-3,X
sta stack-3,X
jsr NoRelocate1 make sure the operand is not relocatable
rts
;
; Value - constant value
;
Value anop
jsr CheckStack make sure there is room on the stack
ldy #1 place the value on the stack
ldx sp
lda [ep],Y
sta stack,X
ldy #3
lda [ep],Y
sta stack+2,X
short M value is not relocatable
lda #0
sta stack+4,X
long M
add4 ep,#5 skip the op code and operand
add2 sp,#5 reserve space on the operand stack
rts
;
; Weak - weak reference to a label
;
Weak anop
inc4 ep skip the op code
ph4 ep find the symbol value
ph2 #0
jsr GetSymbolValue
jsr CheckStack make sure there is room on the stack
lda symbolValue save the value
sta stack,X
lda symbolValue+2
sta stack+2,X
short M set the relocation flag
lda symbolRelocatable
sta stack+4,X
long M
add2 sp,#5 reserve space on the operand stack
lda [ep] skip the name in the segment
and #$00FF
sec
adc ep
sta ep
bcc wk1
inc ep+2
wk1 rts
;
; Table of expression handling subroutines
;
addr dc a'EndExp' $00 End
dc a'Add' $01 +
dc a'Sub' $02 -
dc a'Mul' $03 *
dc a'Div' $04 div
dc a'Mod' $05 mod
dc a'UMinus' $06 unary -
dc a'Shift' $07 << or >>
dc a'And' $08 and
dc a'Or' $09 or
dc a'Eor' $0A eor
dc a'Not' $0B not
dc a'LE' $0C <=
dc a'GE' $0D >=
dc a'NE' $0E <>
dc a'LT' $0F <
dc a'GT' $10 >
dc a'EQ' $11 =
dc a'BAnd' $12 &
dc a'BOr' $13 |
dc a'BEor' $14 bitwise eor
dc a'BNot' $15 bitwise not
dc 10a'Invalid' $16..$1F unused
dc 16a'Invalid' $20..$2F unused
dc 16a'Invalid' $30..$3F unused
dc 16a'Invalid' $40..$4F unused
dc 16a'Invalid' $50..$5F unused
dc 16a'Invalid' $60..$6F unused
dc 16a'Invalid' $70..$7F unused
dc a'PCounter' $80 program counter
dc a'Value' $81 absolute value
dc a'Weak' $82 weak label reference
dc a'Reference' $83 strong label reference
dc a'AttrLength' $84 length attribute
dc a'AttrType' $85 type attribute
dc a'AttrCount' $86 count attribute
dc a'SegDisp' $87 disp from start of segment
dc 8a'Invalid' $88-8F unused
dc 16a'Invalid' $90..$9F unused
dc 16a'Invalid' $A0..$AF unused
dc 16a'Invalid' $B0..$BF unused
dc 16a'Invalid' $C0..$CF unused
dc 16a'Invalid' $D0..$DF unused
dc 16a'Invalid' $E0..$EF unused
dc 16a'Invalid' $F0..$FF unused
ret
end
****************************************************************
*
* SCmp4 - Four byte signed integer compare
*
* Inputs:
* 7,S - first argument
* 3,S - second argument
*
* Outputs:
* C - set if 7,S >= 3,S, else clear
* Z - set if 7,S = 3,S, else clear
*
****************************************************************
*
SCmp4 private
lda 9,S branch if both numbers have the same
eor 5,S sign
bpl cp1
lda 5,S do a comparison of oppositely signed
cmp 9,S numbers
rts
cp1 lda 9,S do a comparison of numbers with the
cmp 5,S same sign
bne cp2
lda 7,S
cmp 3,S
cp2 rts
end