#if !defined (__M68881__) && !defined (sfp004) | add exponent to floating point number | C Interface | double ldexp(double value, unsigned int exp); | returns value * 2**exp | (int is 16 bits if -mshort, 32 bits if !-mshort) |----------------------------------------------------------------------------- | ported to 68000 by Kai-Uwe Bloem, 12/89 | #1 original author: Peter S. Housel 9/21/88,01/17/89,03/19/89,5/24/89 | #2 added support for denormalized numbers -kub-, 01/90 | #3 ported to gcc ++jrb 04/90 | #4 handle exponent overflow when ints are 32 bits -kub-, 04/90 |----------------------------------------------------------------------------- .text; .even .globl _ldexp .globl __infinitydf #ifdef ERROR_CHECK _Overflow: .ascii "ldexp: OVERFLOW\12\15\0" .even #endif ERROR_CHECK _ldexp: lea sp@(4),a1 moveml d2-d7,sp@- | save d2-d7 movew a1@,d0 | extract value.exp movew d0,d2 | extract value.sign lsrw #4,d0 andw #0x7ff,d0 | kill sign bit andw #0x0f,a1@ | remove exponent from value.mantissa tstw d0 | check for zero exponent - no leading 1 beq 0f orw #0x10,a1@ | restore implied leading 1 bra 1f 0: addw #1,d0 1: #ifdef __MSHORT__ addw a1@(8),d0 | add in exponent extl d0 #else extl d0 addl a1@(8),d0 | add in exponent #endif cmpl #-53,d0 | hmm. works only if 1 in implied position... ble retz | range error - underflow cmpl #2047,d0 bge rangerr | range error - overflow clrw d1 | zero rounding bits moveml a1@,d4-d5 | value into d4,d5 jmp norm_df | norm_df will pop d2-d7 and rts .globl _errno | from ERANGE = 63 retz: moveq #0,d0 | zero return value moveq #0,d1 jra L0 rangerr: #ifdef ERROR_CHECK # ifdef __MSHORT__ movew #ERANGE,_errno | set errno # else movel #ERANGE,_errno | set errno # endif moveml d0-d1,a7@- pea _Overflow | for printf pea __iob+52 | jbsr _fprintf | addql #8,a7 | moveml a7@+,d0-d1 #endif ERROR_CHECK moveml __infinitydf,d0-d1 | return HUGE_VAL (same as in ) andw #0x8000,d2 | get sign bit of argument swap d2 clrw d2 orl d2,d0 L0: moveml sp@+,d2-d7 | pop saved reggies rts #else __M68881__ || sfp004 #ifdef __M68881__ |####################################################################### | |# add exponent to floating point number |# C Interface |# double ldexp(double value, unsigned int exp); |# returns value * 2**exp |# (int is 16 bits if -mshort, 32 bits if !-mshort) |# performed entirely on the 68881 to avoid overfow as good as possible |############################################################################## |# hacked for the 68881 by Michael Ritzert, 5.10.90 |############################################################################## |# ported fromt sfp004 to real coprocessor, mjr, August 1991 |################################################################################ .text; .even .globl _ldexp #ifdef ERROR_CHECK _Domain: .ascii "ldexp: NAN\12\15\0" _Overflow: .ascii "ldexp: OVERFLOW\12\15\0" .even double_max: .long 0x7fee42d1 .long 0x30273b76 double_min: .long 0xffee42d1 .long 0x30273b76 NaN: .long 0x7fffffff .long 0xffffffff p_Inf: .long 0x7ff00000 .long 0x00000000 m_Inf: .long 0xfff00000 .long 0x00000000 .even #endif ERROR_CHECK _ldexp: #ifdef __MSHORT__ movew a7@(12),d0 | get exponent extl d0 #else movel a7@(12),d0 | get exponent #endif fgetexpd a7@(4),fp1 | extract exponent of 1st arg fmovel fp1,d1 | d1 serves as accumulator addl d0,d1 | sum of exp_s of both args ftwotoxl d0,fp0 | ftwotox to fp0 (as long int!) fmuld a7@(4),fp0 | fmul value,fp0 fmoved fp0,a7@- | get double from fp0 moveml a7@+,d0-d1 #endif __M68881__ #ifdef sfp004 | add exponent to floating point number | C Interface | double ldexp(double value, unsigned int exp); | returns value * 2**exp | (int is 16 bits if -mshort, 32 bits if !-mshort) | performed entirely on the 68881 to avoid overfow as good as possible | | hacked for the 68881 by Michael Ritzert, 5.10.90 | | addresses of the 68881 data port. This choice is fastest when much data is | transferred between the two processors. comm = -6 | fpu command reg resp = -16 | fpu response reg zahl = 0 | fpu data reg | waiting loop ... | | wait: | ww: cmpiw #0x8900,a1@(resp) | beq ww | is coded directly by | .byte 0x0c,0x69,0x89,0x00,0xff,0xf0,0x67,0xf8 (a1) | or | .long 0x0c6889000, 0x000067f8 (a0) .text; .even .globl _ldexp #ifdef ERROR_CHECK _Domain: .ascii "ldexp: NAN\12\15\0" _Overflow: .ascii "ldexp: OVERFLOW\12\15\0" .even double_max: .long 0x7fee42d1 .long 0x30273b76 double_min: .long 0xffee42d1 .long 0x30273b76 NaN: .long 0x7fffffff .long 0xffffffff p_Inf: .long 0x7ff00000 .long 0x00000000 m_Inf: .long 0xfff00000 .long 0x00000000 .even #endif ERROR_CHECK _ldexp: lea 0xfffa50,a0 | fpu address movew #0x4011,a0@(comm) | ftwotox to fp0 (as long int!) #ifdef __MSHORT__ movew a7@(12),d0 | get exponent extl d0 #else movel a7@(12),d0 | get exponent #endif cmpiw #0x8900,a0@(resp) | check if fpu is ready movel d0,a0@ | push arg .long 0x0c6889000, 0xfff067f8 | wait movew #0x5423,a0@(comm) | fmul value,fp0 .long 0x0c6889000, 0xfff067f8 | wait movel a7@(4),a0@ | load value movel a7@(8),a0@ | .long 0x0c6889000, 0xfff067f8 | wait movew #0x7400,a0@(comm) | get double from fp0 .long 0x0c6889000, 0xfff067f8 | wait movel a0@,d0 movel a0@,d1 #endif sfp004 #ifdef ERROR_CHECK lea double_max,a0 | swap d0 | exponent into lower word cmpw a0@(16),d0 | == NaN ? beq error_nan | cmpw a0@(24),d0 | == + Infinity ? beq error_plus | swap d0 | result ok, rts | restore d0 # ifndef __MSHORT__ error_plus: swap d0 movel #63,_errno | Overflow: errno = ERANGE moveml d0-d1,a7@- | print error message pea _Domain | for printf bra error_exit | error_nan: moveml a0@(24),d0-d1 | result = +inf movel #62,_errno | NAN => errno = EDOM moveml d0-d1,a7@- | print error message pea _Overflow | for printf # else __MSHORT__ error_plus: swap d0 movew #63,_errno | Overflow: errno = ERANGE moveml d0-d1,a7@- | print error message pea _Domain | for printf bra error_exit | error_nan: moveml a0@(24),d0-d1 | result = +inf movew #62,_errno | NAN => errno = EDOM moveml d0-d1,a7@- | print error message pea _Overflow | for printf # endif __MSHORT__ error_exit: pea __iob+52 | jbsr _fprintf | addql #8,a7 | moveml a7@+,d0-d1 rts #else ERROR_CHECK rts #endif ERROR_CHECK #endif /* !__M68881__ && !sfp004 */