Mercurial > hg > index.cgi
changeset 112:98b0646360e1
Fix division by zero detection to actually work for integer division
| author | William Astle <lost@l-w.ca> |
|---|---|
| date | Tue, 26 Dec 2023 21:50:09 -0700 |
| parents | b10f6c8979a5 |
| children | 0aac26453849 |
| files | src/int.s |
| diffstat | 1 files changed, 6 insertions(+), 7 deletions(-) [+] |
line wrap: on
line diff
--- a/src/int.s Tue Dec 26 21:44:10 2023 -0700 +++ b/src/int.s Tue Dec 26 21:50:09 2023 -0700 @@ -357,15 +357,14 @@ sbcb fpa0+fpa.sig+1 sbca fpa0+fpa.sig std fpa0+fpa.sig -int32_div1 ldb fpa1+fpa.sig ; check for division by zero - orb fpa1+fpa.sig+1 - orb fpa1+fpa.sig+2 - orb fpa1+fpa.sig+3 - lbne DIV0ERROR ; brif division by zero - bsr util_div32 ; do the actual division +int32_div1 ldd fpa1+fpa.sig ; is MSW zero? + bne int32_div1a ; brif not - not division by zero + ldd fpa1+fpa.sig+2 + lbeq DIV0ERROR ; brif LSW is zero - division by zero +int32_div1a bsr util_div32 ; do the actual division lda ,s+ ; get desired sign bmi int32_div2 ; brif want negative - we can't overflow in that case - ldb fpaextra ; get high byte of result + ldb fpaextra ; get high byte of result lbmi OVERROR2 ; brif we ended up with 0x80000000 positive bra int32_div3 ; go return result int32_div2 ldd zero ; negate result to correct sign