diff options
Diffstat (limited to 'libc/i386fp/fpushd.x')
| -rw-r--r-- | libc/i386fp/fpushd.x | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/libc/i386fp/fpushd.x b/libc/i386fp/fpushd.x new file mode 100644 index 0000000..68caab0 --- /dev/null +++ b/libc/i386fp/fpushd.x @@ -0,0 +1,60 @@ +! bcc 386 floating point routines (version 2) -- dtof, Fpushd, Fneg, Fnegd +! authors: Timothy Murphy (tim@maths.tcd.ie), Bruce Evans + +#include "fplib.h" + + .extern Fpullf + +! dtof converts the double at [ebx] to a float and pushes the float onto +! the stack (D_SIZE bytes are allocated for the float although only the bottom +! F_SIZE are used). +! This is a quickly-written slowish version. + + .globl dtof + .align ALIGNMENT +dtof: + pop eax + sub esp,#D_SIZE ! build result here + push eax ! put back return address + call Fpushd + lea ebx,D_SIZE+PC_SIZE[esp] + call Fpullf + ret + +! Push double at address [ebx] onto stack + + .globl Fpushd + .align ALIGNMENT +Fpushd: + pop ecx + push dword D_HIGH[ebx] + push dword D_LOW[ebx] + jmp ecx ! return + +! Push double at address [ebx] onto stack, negating it on the way. + +! Don't worry about generating -0 because other routines have to allow for +! it anyway. + +! Perhaps this and Fneg should check for denormals and illegal operands +! (I think only signalling NaNs are illegal). +! fchs doesn't check, but fld does. +! Our Fpushd is not quite like fld because no conversions are involved. + + .globl Fnegd + .align ALIGNMENT +Fnegd: + pop ecx + mov eax,D_HIGH[ebx] + xor eax,#D_SIGN_MASK ! toggle sign + push eax + push dword D_LOW[ebx] + jmp ecx ! return + +! Negate double on stack + + .globl Fneg + .align ALIGNMENT +Fneg: + xorb PC_SIZE+D_SIZE-1[esp],D_SIGN_MASK >> (REG_BIT-CHAR_BIT) ! toggle sign + ret |