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New code for the shift functions

git-svn-id: svn://svn.cc65.org/cc65/trunk@3143 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
cuz 2004-07-05 22:24:06 +00:00
parent 07419b62f8
commit c122f18605
7 changed files with 240 additions and 406 deletions

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@ -29,6 +29,7 @@ OBJS = add.o \
asleax2.o \
asleax3.o \
asleax4.o \
asr.o \
asrax1.o \
asrax2.o \
asrax3.o \

60
libsrc/runtime/asr.s Normal file
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@ -0,0 +1,60 @@
;
; Ullrich von Bassewitz, 2004-06-30
;
; CC65 runtime: right shift support for ints
;
; Note: The standard declares a shift count that is negative or >= the
; bitcount of the shifted type for undefined behaviour.
;
; Note^2: The compiler knowns about the register/zero page usage of this
; function, so you need to change the compiler source if you change it!
;
.export tosasrax
.import popax
.importzp tmp1
tosasrax:
and #$0F ; Bring the shift count into a valid range
sta tmp1 ; Save it
jsr popax ; Get the left hand operand
ldy tmp1 ; Get shift count
beq L9 ; Bail out if shift count zero
cpy #8 ; Shift count 8 or greater?
bcc L1 ; Jump if not
; Shift count is greater 8. The carry is set when we enter here.
tya
sbc #8
tay ; Adjust shift count
txa
ldx #$00 ; Shift by 8 bits
cmp #$00 ; Test sign bit
bpl L1
dex ; Make X the correct sign extended value
; Save the high byte so we can shift it
L1: stx tmp1 ; Save high byte
jmp L3
; Do the actual shift
L2: cpx #$80 ; Copy bit 15 into the carry
ror tmp1
ror a
L3: dey
bpl L2
; Done with shift
ldx tmp1
L9: rts

44
libsrc/runtime/lasr.s Normal file
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@ -0,0 +1,44 @@
;
; Ullrich von Bassewitz, 2004-06-30
;
; CC65 runtime: right shift support for longs
;
; Note: The standard declares a shift count that is negative or >= the
; bitcount of the shifted type for undefined behaviour.
;
; Note^2: The compiler knowns about the register/zero page usage of this
; function, so you need to change the compiler source if you change it!
;
.export tosasreax
.import popeax
.importzp sreg, tmp1
tosasreax:
and #$1F ; Bring the shift count into a valid range
sta tmp1 ; Save it
jsr popeax ; Get the left hand operand
ldy tmp1 ; Get shift count
beq L9 ; Bail out if shift count zero
stx tmp1 ; Save byte 1
ldx sreg+1 ; Load byte 3
; Do the actual shift. Faster solutions are possible but need a lot more code.
L2: cpx #$80 ; Copy bit 31 into the carry
ror sreg+1
ror sreg
ror tmp1
ror a
dey
bne L2
; Shift done
ldx tmp1
L9: rts

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@ -1,95 +1,44 @@
;
; Ullrich von Bassewitz, 20.09.1998
; Ullrich von Bassewitz, 2004-06-30
;
; CC65 runtime: left shift support for longs
; CC65 runtime: left shift support for long and unsigned long
;
; Note: The standard declares a shift count that is negative or >= the
; bitcount of the shifted type for undefined behaviour.
;
; Note^2: The compiler knowns about the register/zero page usage of this
; function, so you need to change the compiler source if you change it!
;
.export tosasleax, tosshleax
.import addysp1
.importzp sp, sreg, ptr1, ptr2
.import popeax
.importzp sreg, tmp1
tosshleax:
tosasleax:
and #$1F ; Bring the shift count into a valid range
sta tmp1 ; Save it
; Get the lhs from stack into ptr1/ptr2
jsr popeax ; Get the left hand operand
pha
ldy #0
lda (sp),y
sta ptr1
iny
lda (sp),y
sta ptr1+1
iny
lda (sp),y
sta ptr2
iny
lda (sp),y
sta ptr2+1
pla
jsr addysp1
ldy tmp1 ; Get shift count
beq L9 ; Bail out if shift count zero
stx tmp1 ; Save byte 1
; Check for shift overflow or zero shift
; Do the actual shift. Faster solutions are possible but need a lot more code.
tay ; Low byte of shift count into y
txa ; Get byte 2
ora sreg
ora sreg+1 ; Check high 24 bit
bne @L6 ; Shift count too large
cpy #32
bcs @L6
cpy #0 ; Shift count zero?
beq @L5
; We must shift. Shift by multiples of eight if possible
tya
@L1: cmp #8
bcc @L3
sbc #8
ldx ptr2
stx ptr2+1
ldx ptr1+1
stx ptr2
ldx ptr1
stx ptr1+1
ldx #0
stx ptr1
beq @L1
; Shift count is now less than eight. Do a real shift.
@L3: tay ; Shift count to Y
lda ptr1 ; Get one byte into A for speed
cpy #0
beq @L4a ; Jump if done
@L4: asl a
rol ptr1+1
rol ptr2
rol ptr2+1
dey
bne @L4
; Put the result in place
@L4a: ldx ptr2
stx sreg
ldx ptr2+1
stx sreg+1
ldx ptr1+1
@L5: rts
; Jump here if shift count overflow
@L6: lda #0
sta sreg+1
sta sreg
tax
rts
L2: asl a
rol tmp1
rol sreg
rol sreg+1
dey
bne L2
; Shift done
ldx tmp1
L9: rts

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@ -1,181 +1,44 @@
;
; Ullrich von Bassewitz, 20.09.1998
; Ullrich von Bassewitz, 2004-06-30
;
; CC65 runtime: right shift support for longs
; CC65 runtime: right shift support for unsigned longs
;
; Note: The standard declares a shift count that is negative or >= the
; bitcount of the shifted type for undefined behaviour.
;
; Note^2: The compiler knowns about the register/zero page usage of this
; function, so you need to change the compiler source if you change it!
;
.export tosasreax, tosshreax
.import addysp1
.importzp sp, sreg, ptr1, ptr2
; --------------------------------------------------------------------
; signed shift
.proc tosasreax
jsr getlhs ; Get the lhs from the stack
jsr checkovf ; Check for overflow
bcs L6 ; Jump if shift count too large
cpy #0 ; Shift count zero?
beq L5
; We must shift. Shift by multiples of eight if possible
tya
L1: cmp #8
bcc L3
sbc #8
ldx ptr1+1
stx ptr1
ldx ptr2
stx ptr1+1
ldy #0
ldx ptr2+1
stx ptr2
bpl L2
dey ; Get sign
L2: sty ptr2+1
jmp L1
; Shift count is now less than eight. Do a real shift.
L3: tay ; Shift count to Y
lda ptr2+1 ; Get one byte into A for speed
cpy #0
beq L4a ; Jump if done
L4: cmp #$80 ; Get sign bit into C
ror a
ror ptr2
ror ptr1+1
ror ptr1
dey
bne L4
; Put the result in place
L4a: sta sreg+1
lda ptr2
sta sreg
ldx ptr1+1
lda ptr1
L5: rts
; Jump here if shift count overflow
L6: ldx #0
lda ptr2+1 ; Check sign
bpl L7
dex
L7: stx sreg+1
stx sreg
txa
rts
.endproc
; --------------------------------------------------------------------
; unsigned shift
.proc tosshreax
jsr getlhs ; Get the lhs from the stack
jsr checkovf ; Check for overflow
bcs L6 ; Jump if shift count too large
cpy #0 ; Shift count zero?
beq L5
; We must shift. Shift by multiples of eight if possible
tya
L1: cmp #8
bcc L3
sbc #8
ldx ptr1+1
stx ptr1
ldx ptr2
stx ptr1+1
ldx ptr2+1
stx ptr2
ldx #0
stx ptr2+1
beq L1
; Shift count is now less than eight. Do a real shift.
L3: tay ; Shift count to Y
lda ptr2+1 ; Get one byte into A for speed
cpy #0
beq L4a ; Jump if done
L4: lsr a
ror ptr2
ror ptr1+1
ror ptr1
dey
bne L4
; Put the result in place
L4a: sta sreg+1
lda ptr2
sta sreg
ldx ptr1+1
lda ptr1
L5: rts
; Jump here if shift count overflow
L6: lda #0
sta sreg+1
sta sreg
tax
rts
.endproc
; --------------------------------------------------------------------
; Helpers
.proc getlhs ; Get the lhs from stack into ptr1/ptr2
pha
ldy #0
lda (sp),y
sta ptr1
iny
lda (sp),y
sta ptr1+1
iny
lda (sp),y
sta ptr2
iny
lda (sp),y
sta ptr2+1
pla
jmp addysp1
.endproc
.export tosshreax
.import popeax
.importzp sreg, tmp1
.proc checkovf ; Check for shift overflow
tosshreax:
and #$1F ; Bring the shift count into a valid range
sta tmp1 ; Save it
tay ; Low byte of shift count into y
txa ; Get byte 2
ora sreg
ora sreg+1 ; Check high 24 bit
bne TooLarge ; Shift count too large
cpy #32
bcc Ok
TooLarge:
sec
Ok: rts
.endproc
jsr popeax ; Get the left hand operand
ldy tmp1 ; Get shift count
beq L9 ; Bail out if shift count zero
stx tmp1 ; Save byte 1
; Do the actual shift. Faster solutions are possible but need a lot more code.
L2: lsr sreg+1
ror sreg
ror tmp1
ror a
dey
bne L2
; Shift done
ldx tmp1
L9: rts

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@ -1,69 +1,58 @@
;
; Ullrich von Bassewitz, 05.08.1998
; Ullrich von Bassewitz, 1998-08-05, 2004-06-25
;
; CC65 runtime: left shift support for ints
; CC65 runtime: left shift support for ints and unsigneds
;
; Note: The standard declares a shift count that is negative or >= the
; bitcount of the shifted type for undefined behaviour.
;
; Note^2: The compiler knowns about the register/zero page usage of this
; function, so you need to change the compiler source if you change it!
;
.export tosasla0, tosaslax, tosshla0, tosshlax
.import popsreg, return0
.importzp sreg
tosshla0:
tosasla0:
ldx #0
.export tosaslax, tosshlax
.import popax
.importzp tmp1
tosshlax:
tosaslax:
jsr popsreg ; get TOS into sreg
cpx #0
bne TooLarge
cmp #16
bcs TooLarge
and #$0F ; Bring the shift count into a valid range
sta tmp1 ; Save it
cmp #8 ; Shift count greater 8?
beq L3 ; Jump if exactly 8
bcc L1 ; Jump if no
jsr popax ; Get the left hand operand
; Shift count is greater 8. Do the first 8 bits the fast way
ldy tmp1 ; Get shift count
beq L9 ; Bail out if shift count zero
ldy sreg
sty sreg+1
stx sreg ; Low byte = 0
sec
sbc #8
cpy #8 ; Shift count 8 or greater?
bcc L3 ; Jump if not
; Shift count less than 8 if we come here
; Shift count is greater 7. The carry is set when we enter here.
L1: tay ; Shift count --> Y
beq Zero ; Done if shift count zero
tax
tya
sbc #8
tay
txa
jmp L2
L1: asl a
L2: dey
bpl L1
tax
lda #$00
rts
lda sreg ; get low byte for faster shift
; Shift count is less than 8.
; Do the actual shift
L2: asl a
rol sreg+1
dey
bne L2
L3: stx tmp1 ; Save high byte of lhs
L4: asl a
rol tmp1
dey
bne L4
; Done with shift
ldx sreg+1
rts
; Shift count == 8
L3: txa ; X == 0, now A == 0
ldx sreg
rts
; Shift count was zero
Zero: lda sreg
ldx sreg+1
rts
; Shift count too large, result is zero
TooLarge:
jmp return0
ldx tmp1
L9: rts

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@ -1,127 +1,55 @@
;
; Ullrich von Bassewitz, 05.08.1998
; Ullrich von Bassewitz, 2004-06-30
;
; CC65 runtime: right shift support for ints
; CC65 runtime: right shift support for unsigneds
;
; Note: The standard declares a shift count that is negative or >= the
; bitcount of the shifted type for undefined behaviour.
;
; Note^2: The compiler knowns about the register/zero page usage of this
; function, so you need to change the compiler source if you change it!
;
; --------------------------------------------------------------------
; signed shift
.export tosshrax
.import popax
.importzp tmp1
.export tosasra0, tosasrax
.import popsreg, return0
.importzp sreg
tosasra0:
ldx #0
tosasrax:
jsr popsreg ; get TOS into sreg
cpx #0
bne TooLarge
cmp #16
bcs TooLarge
cmp #8 ; Shift count greater 8?
beq L4 ; Jump if exactly 8
bcc L2 ; Jump if no
; Shift count is greater 8. Do the first 8 bits the fast way
ldy #0
ldx sreg+1
stx sreg
bpl L1
dey ; Create correct sign bits
L1: sty sreg+1
sec
sbc #8
; Shift count less than 8 if we come here
L2: tay ; Shift count --> Y
beq Zero ; Done if shift count zero
lda sreg ; get low byte for faster shift
ldx sreg+1 ; get high byte
; Do the actual shift
L3: cpx #$80 ; get bit 7 into carry
ror sreg+1
ror a
dey
bne L3
; Done with shift
ldx sreg+1
rts
; Shift count == 8
L4: lda sreg+1 ; X is zero
bpl *+3
dex ; X == 0xFF
rts
; Shift count was zero
Zero: lda sreg
ldx sreg+1
rts
; Shift count too large, result is zero
TooLarge:
jmp return0
; --------------------------------------------------------------------
; unsigned shift
.export tosshra0, tosshrax
tosshra0:
ldx #0
tosshrax:
jsr popsreg ; get TOS into sreg
cpx #0
bne TooLarge
cmp #16
bcs TooLarge
and #$0F ; Bring the shift count into a valid range
sta tmp1 ; Save it
cmp #8 ; Shift count greater 8?
beq L8 ; Jump if exactly 8
bcc L6 ; Jump if no
jsr popax ; Get the left hand operand
; Shift count is greater 8. Do the first 8 bits the fast way
ldy tmp1 ; Get shift count
beq L9 ; Bail out if shift count zero
sbc #8 ; Carry already set
ldy sreg+1
sty sreg
stx sreg+1 ; High byte = 0
cpy #8 ; Shift count 8 or greater?
bcc L3 ; Jump if not
; Shift count less than 8 if we come here
; Shift count is greater 7. The carry is set when we enter here.
L6: tay ; Shift count --> Y
beq Zero ; Done if shift count zero
tya
sbc #8
tay ; Adjust shift count
txa
ldx #$00 ; Shift by 8 bits
beq L2 ; Branch always
L1: lsr a
L2: dey
bpl L1
rts
lda sreg ; get low byte for faster shift
; Shift count is less than 8. Do the actual shift.
; Do the actual shift
L7: lsr sreg+1
ror a
dey
bne L7
L3: stx tmp1 ; Save high byte of lhs
L4: lsr tmp1
ror a
dey
bne L4
; Done with shift
ldx sreg+1
rts
; Shift count == 8
L8: lda sreg+1 ; X is zero
rts
ldx tmp1
L9: rts