diff options
Diffstat (limited to 'bin86-0.3/bccfp/fcomp.x')
| -rw-r--r-- | bin86-0.3/bccfp/fcomp.x | 89 |
1 files changed, 0 insertions, 89 deletions
diff --git a/bin86-0.3/bccfp/fcomp.x b/bin86-0.3/bccfp/fcomp.x deleted file mode 100644 index 71148ab..0000000 --- a/bin86-0.3/bccfp/fcomp.x +++ /dev/null @@ -1,89 +0,0 @@ -! bcc 386 floating point routines (version 2) -- Fcomp, Fcompd, Fcompf -! authors: Timothy Murphy (tim@maths.tcd.ie), Bruce Evans - -#include "fplib.h" - - .extern Fpushf - -! Pop 2 doubles from stack and compare them, return result in flags so -! normal signed branches work (unlike 80x87 which returns the result in -! the zero and carry flags). - - .globl Fcomp - .align ALIGNMENT -Fcomp: - pop ecx ! get return address - pop eax ! xl - pop edx ! xu - push ecx ! put back ret address - pop 2nd double later - -! All this popping is bad on 486's since plain mov takes 1+ cycle and pop -! takes 4 cycles. But this code is designed for 386's where popping is -! nominally the same speed and saves code space and so maybe instruction -! fetch time as well as the instruction to adjust the stack (ret #n takes -! no longer than plain ret but inhibits gotos). - - mov ebx,PC_SIZE+D_LOW[esp] ! yl - mov ecx,PC_SIZE+D_HIGH[esp] ! yu - jmp compare - -! Pop double from stack and compare with double at [ebx] - - .globl Fcompd - .align ALIGNMENT -Fcompd: - mov eax,PC_SIZE+D_LOW[esp] ! xl - mov edx,PC_SIZE+D_HIGH[esp] ! xu - mov ecx,D_HIGH[ebx] ! yu - mov ebx,D_LOW[ebx] ! yl - -compare: - test edx,#D_SIGN_MASK ! is x >= 0? - jz cmp0 ! yes; just compare x and y - test ecx,#D_SIGN_MASK ! no; but is y >= 0? - jz cmp0 ! yes; just compare x and y - - xchg edx,ecx ! x, y < 0, so ... - xchg eax,ebx ! ... swap x and y ... - xor edx,#D_SIGN_MASK ! ... and toggle signs - xor ecx,#D_SIGN_MASK - -cmp0: - cmp edx,ecx ! compare upper dwords - jnz checkneg0 ! if upper dwords differ, job is almost done - mov edx,eax ! upper dwords equal, so ... - mov ecx,ebx ! ... must make unsigned comparison of lower dwords - shr edx,#1 ! shift past sign - shr ecx,#1 - cmp edx,ecx ! compare top 31 bits of lower dwords - jnz return ! if these differ, job is done - and eax,#1 ! compare lowest bits - and ebx,#1 - cmp eax,ebx - -return: - ret #D_SIZE ! return, popping 1 double from stack - -checkneg0: - test edx,#D_EXP_MASK | D_FRAC_MASK ! check to catch unusual case ... - jnz recheck - test eax,eax - jnz recheck - test ecx,#D_EXP_MASK | D_FRAC_MASK - jnz recheck - test ebx,ebx - jz return ! ... both are (+-) zero, return 'z' - -recheck: - cmp edx,ecx ! the upper words were really different - ret #D_SIZE - - .globl Fcompf - .align ALIGNMENT -Fcompf: - call Fpushf - pop ebx ! yl - pop ecx ! yu - mov eax,PC_SIZE+D_LOW[esp] ! xl - mov edx,PC_SIZE+D_HIGH[esp] ! xu - jmp compare |