empathicqubit/cc65
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Reestablished entry state of signed operation and optimized that (again).

Browse source
This commit is contained in:
IrgendwerA8 2018-05-25 23:18:26 +02:00
parent ba5b580368
commit 8a5d1b9674
4 changed files with 74 additions and 54 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

22
libsrc/runtime/absvaludiv16.s
View file

@ -1,22 +0,0 @@
;
; Christian Krueger, 23-May-2018
;
; CC65 runtime: helper call for mod/div with signed ints
;
; When negating values, we will ignore the possibility here, that one of the
; values is $8000, in which case the negate will fail.
.export absvaludiv16
.import _abs, popax, udiv16
.importzp ptr1, ptr4
absvaludiv16:
jsr _abs
sta ptr4
stx ptr4+1 ; Save right absolute operand
jsr popax
jsr _abs
sta ptr1
stx ptr1+1 ; Save left absolute operand
jmp udiv16

38
libsrc/runtime/div.s
View file

@ -1,5 +1,5 @@
;
; Christian Krueger, 24-May-2018
; Ullrich von Bassewitz, 07.08.1998
;
; CC65 runtime: division for signed ints
;
@ -8,22 +8,30 @@
; values is $8000, in which case the negate will fail.
.export tosdiva0, tosdivax
.import absvaludiv16, negax
.importzp sp, ptr1, tmp1
.import popsargsudiv16, negax
.importzp ptr1, tmp1, tmp2
tosdiva0:
ldx #0
tosdivax:
pha ; Check if high-bytes indicate
txa ; different sign, so that we have to
ldy #1 ; negate the result after the operation.
eor (sp),y ; Eor with lhs high byte
sta tmp1 ; Save post negation indicator to tmp1
pla ; Back to entry accu
jsr absvaludiv16
ldx ptr1+1
lda ptr1
ldy tmp1 ; Fetch indicator
bmi negate
jsr popsargsudiv16 ; Get arguments from stack, adjust sign
; and do the division
ldx ptr1+1 ; Load high byte of result
; Adjust the sign of the result. tmp1 contains the high byte of the left
; operand, tmp2 contains the high byte of the right operand.
lda tmp1
eor tmp2
bpl Pos ; Jump if sign of result positive
; Result is negative
lda ptr1 ; Load low byte of result
jmp negax ; Adjust the sign
; Result is positive
Pos: lda ptr1 ; Load low byte of result
rts
negate: jmp negax

39
libsrc/runtime/mod.s
View file

@ -1,5 +1,5 @@
;
; Christian Krueger, 24-May-2018
; Ullrich von Bassewitz, 07.08.1998
;
; CC65 runtime: modulo operation for signed ints
;
@ -8,25 +8,30 @@
; values is $8000, in which case the negate will fail.
.export tosmoda0, tosmodax
.import absvaludiv16, negax
.importzp sp, sreg, tmp1
.import popsargsudiv16, negax
.importzp sreg, tmp1
tosmoda0:
ldx #0
tosmodax:
jsr popsargsudiv16 ; Get arguments from stack, adjust sign
; and do the division
lda sreg ; Load low byte of result
ldx sreg+1 ; Load high byte of result
; Prepare adjustment of the sign of the result. The sign of the result of the
; modulo operation is the same as that of the left operand.
; Adjust the sign of the result. tmp1 contains the high byte of the left
; operand, tmp2 contains the high byte of the right operand. The sign of
; the result of the modulo operation is the same as that of the left
; operand
bit tmp1
bpl Pos ; Jump if sign of result positive
; Result is negative
jmp negax ; Adjust the sign
; Result is positive
Pos: rts
pha
ldy #1 ; Prepare lhs operant hi-byte fetch
lda (sp),y
sta tmp1 ; Save post negation indicator to tmp1
pla ; Back to entry accu
jsr absvaludiv16
ldx sreg+1 ; Remainder to return registers
lda sreg
ldy tmp1 ; Fetch indicator
bmi negate
rts
negate: jmp negax

29
libsrc/runtime/shelp.s Normal file
View file

@ -0,0 +1,29 @@
;
; Ullrich von Bassewitz, 07.08.1998
;
; CC65 runtime: helper stuff for mod/div with signed ints
;
; When negating values, we will ignore the possibility here, that one of the
; values is $8000, in which case the negate will fail.
.export popsargsudiv16
.import negax, popax, udiv16
.importzp tmp1, tmp2, ptr1, ptr4
popsargsudiv16:
stx tmp2 ; Remember sign
cpx #0
bpl L1
jsr negax ; Negate accumulator
L1: sta ptr4
stx ptr4+1 ; Save right operand
jsr popax
stx tmp1 ; Remember sign
cpx #0
bpl L2
jsr negax
L2: sta ptr1
stx ptr1+1
jmp udiv16 ; Call the division