projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| e9977b56 C |
1 | |
| 2 | .globl _dmlad | |
| 3 | /* | |
| 4 | routine for destructive multiplication and addition to a bignum by | |
| 5 | two fixnums. | |
| 6 | ||
| 7 | from C, the invocation is dmlad(sdot,mul,add); | |
| 8 | where sdot is the address of the first special cell of the bignum | |
| 9 | mul is the multiplier, add is the fixnum to be added (The latter | |
| 10 | being passed by value, as is the usual case. | |
| 11 | ||
| 12 | ||
| 13 | Register assignments: | |
| 14 | ||
| 15 | r11 = current sdot | |
| 16 | r10 = carry | |
| 17 | r9 = previous sdot, for relinking. | |
| 18 | r8 = temporary kluge variable | |
| 19 | */ | |
| 20 | ||
| 21 | _dmlad: .word 0x0f00 | |
| 22 | movl 4(fp),r11 #initialize cell pointer | |
| 23 | movl 12(fp),r10 #initialize carry | |
| 24 | loop: emul 8(fp),(r11),r10,r0 #r0 gets cell->car times mul + carry | |
| 25 | ||
| 26 | ediv $0x40000000,r0,r10,r8 #cell->car gets prod % 2**30 | |
| 27 | movl r8,(r11) | |
| 28 | #carry gets quotient | |
| 29 | /* extzv $0,$30,r0,(r11) | |
| 30 | extv $30,$32,r0,r10 | |
| 31 | */ | |
| 32 | movl r11,r9 #save last cell for fixup at end. | |
| 33 | movl 4(r11),r11 #move to next cell | |
| 34 | bneq loop #done indicated by 0 for next sdot | |
| 35 | tstl r10 #if carry zero no need to allocate | |
| 36 | beql done #new bigit | |
| 37 | mcoml r10,r3 #test to see if neg 1. | |
| 38 | bneq alloc #if not must allocate new cell. | |
| 39 | tstl (r9) #make sure product isn't -2**30 | |
| 40 | beql alloc | |
| 41 | movl r0,(r9) #save old lower half of product. | |
| 42 | brb done | |
| 43 | alloc: callf $4,_newdot #otherwise allocate new bigit | |
| 44 | movl r10,(r0) #store carry | |
| 45 | movl r0,4(r9) #save new link cell | |
| 46 | done: movl 4(fp),r0 | |
| 47 | ret |