1: .globl flag 2: .globl b1, w1, u1, b1s, b1e 3: / here to allocate a new block 4: / 5: / 6: / mov ...,r0 7: / jsr pc,allocate 8: / mov r1,... 9: / 10: / requested size in bytes in r0 11: / pointer to header of allocated block returned in r1 12: / r0 is preserved 13: / 14: / convert to words, adjust for header, round up 15: / to a power of two 16: / 17: / each block has a four-word header 18: / W - write ptr (also used as link ptr in frlist) 19: / R - read ptr 20: / A - pointer to head of data 21: / L - ptr to (end+1) of data 22: hsz=1024. 23: numb=4. 24: numb2=2*numb 25: w=0 26: r=2 27: a=4 28: l=6 29: / 30: allocate: 31: mov r0,-(sp) 32: mov r2,-(sp) 33: mov r3,-(sp) 34: tst stats 35: bne 1f 36: jsr pc,initl 37: 1: 38: inc stats 39: dec r0 40: bmi 1f 41: jsr pc,log2 42: inc r0 43: 1: asl r0 44: mov r0,-(sp) 45: / 46: / look on free list for block of required size 47: / 48: zzz: 49: mov (sp),r0 50: tst frlist(r0) 51: beq xxx 52: / 53: / found it, allocate and return 54: / 55: mov frlist(r0),r1 56: add $hblk,r1 57: mov (r1),frlist(r0) 58: mov a(r1),r0 59: mov r0,w(r1) 60: mov r0,r(r1) 61: tst (sp)+ 62: mov (sp)+,r3 63: mov (sp)+,r2 64: mov (sp)+,r0 65: / jsr pc,whead 66: rts pc 67: / 68: / no block of required size 69: / look for larger block 70: / 71: xxx: 72: tst (r0)+ 73: cmp r0,$frend-frlist 74: bhis www 75: tst frlist(r0) 76: bne yyy 77: br xxx 78: / 79: / there are no larger blocks; must garbage collect 80: / 81: www: jsr pc,collect 82: tst r0 83: bne zzz 84: / 85: / out of space 86: / 87: mov $1,r0 88: sys write; 1f; 2f-1f 89: 4 90: 1: <Out of space.\n> 91: 2: .even 92: / 93: / split larger block into two smaller pieces and 94: / link together as smaller blocks in the free list. 95: / 96: yyy: 97: mov hblk,r3 /get free header block 98: beq www 99: mov frlist(r0),r1 100: add $hblk,r1 101: mov w(r1),frlist(r0) 102: mov r3,w(r1) 103: add $hblk,r3 104: mov exp2-2(r0),r2 105: add a(r1),r2 106: mov w(r3),hblk 107: mov l(r1),l(r3) 108: mov r2,l(r1) /L 109: mov r2,a(r3) 110: clr w(r3) /W' 111: mov r1,r2 112: sub $hblk,r2 113: mov r2,frlist-2(r0) 114: br zzz 115: / 116: / 117: / here to release a block 118: / 119: / mov ...,r1 120: / jsr pc,release 121: / 122: / pointer to block in r1 123: / 124: release: 125: / 126: / discover that this is a plausible pointer 127: / 128: mov r0,-(sp) 129: jsr pc,preposterous 130: / 131: / find free list index and link block to that entry 132: / 133: inc stats+2 134: mov frlist(r0),w(r1) 135: clr r(r1) 136: sub $hblk,r1 137: mov r1,frlist(r0) 138: clr r1 /self-defense 139: / jsr pc,whead 140: mov (sp)+,r0 141: rts pc 142: / 143: / 144: / jsr pc,collect 145: / 146: / coalesce free storage by rejoining paired blocks 147: / on the free list. 148: / zero is returned in r0 if no paired blocks were found. 149: / 150: collect: 151: mov r1,-(sp) 152: mov r2,-(sp) 153: mov r3,-(sp) 154: mov r4,-(sp) 155: clr useful 156: inc stats+4. 157: clr r0 /start with smallest blocks 158: /r0 contains frlist index 159: loop1: mov $frlist,r1 160: add r0,r1 161: / 162: / try next list member at this level 163: / 164: loop2: mov (r1),r3 165: beq advance /list is empty 166: add $hblk,r3 167: tst (r3) /W 168: beq advance /only one list element 169: / 170: / calculate address of buddy 171: / 172: mov a(r3),r4 173: sub headsz,r4 174: bit exp2(r0),r4 175: beq 2f 176: bic exp2(r0),r4 177: br 1f 178: 2: bis exp2(r0),r4 179: 1: add headsz,r4 180: / 181: / and search for him 182: / 183: loop3: 184: cmp a(r3),r4 185: beq coal 186: mov r3,r2 187: mov w(r3),r3 188: tst r3 189: beq nocoal 190: add $hblk,r3 191: br loop3 192: / 193: / have found a pair; remove both blocks from list, 194: / coalesce them, and put them on next higher list 195: / 196: coal: inc useful 197: mov w(r3),w(r2) /remove him from list 198: mov (r1),r2 199: add $hblk,r2 200: mov r3,r4 201: mov w(r2),w(r1) /remove other one 202: cmp a(r2),a(r4) 203: bgt 1f 204: mov r2,-(sp) 205: mov r4,r2 206: mov (sp)+,r4 207: 1: mov hblk,(r2) 208: clr r(r2) 209: mov headsz,a(r2) 210: mov headsz,l(r2) 211: sub $hblk,r2 212: mov r2,hblk 213: add exp2(r0),l(r4) /L 214: clr r(r4) 215: mov frlist+2(r0),w(r4) 216: sub $hblk,r4 217: mov r4,frlist+2(r0) 218: br loop2 219: / 220: / no buddy found, try next block on this list 221: / 222: nocoal: 223: mov (r1),r1 224: add $hblk,r1 225: br loop2 226: / 227: / advance to next free list 228: / 229: advance: 230: tst (r0)+ 231: cmp r0,$frend-frlist 232: blo loop1 233: mov useful,r0 234: / 235: / restore registers and return 236: / 237: mov (sp)+,r4 238: mov (sp)+,r3 239: mov (sp)+,r2 240: mov (sp)+,r1 241: rts pc 242: / 243: / routine to find integer part of log2(x) 244: / 245: / jsr pc,log2 246: / 247: / r0 = log2(r0) 248: / 249: log2: 250: mov $15.,-(sp) 251: tst r0 252: beq 2f 253: 1: 254: asl r0 255: bcs 2f 256: dec (sp) 257: br 1b 258: 2: 259: mov (sp)+,r0 260: rts pc 261: / 262: 0 263: exp2: 264: 1;2;4;10;20;40;100;200;400;1000;2000;4000; 265: 10000;20000;40000;100000 266: / 267: / routine to discover whether r1 points to 268: / a plausible header - to avoid ruination. 269: / 270: / r1 is preserved and r0 gets a suitable index for frlist 271: / 272: / jsr pc,preposterous 273: / 274: plausible: 275: cmp r1,$strbuf 276: blo botch 277: cmp r1,$strend 278: bhis botch 279: rts pc 280: / 281: / 282: botch: 283: mov r0,-(sp) 284: mov $1,r0 285: sys write; 1f; 2f-1f 286: 4 287: 1: <Error in allocator.\n> 288: 2: .even 289: / 290: / 291: preposterous: 292: cmp r1,$strbuf 293: blo botch 294: cmp r1,$strend 295: bhis botch 296: cmp a(r1),headsz /A 297: blo botch 298: cmp l(r1),datadr /L 299: bhi botch 300: mov l(r1),r0 /L 301: sub a(r1),r0 /A 302: mov r0,-(sp) 303: jsr pc,log2 304: asl r0 305: cmp exp2(r0),(sp) 306: bne botch 307: mov r0,(sp) 308: mov frlist(r0),r0 309: 1: beq 1f 310: add $hblk,r0 311: cmp r0,r1 312: beq botch 313: mov (r0),r0 314: br 1b 315: 1: mov (sp)+,r0 316: rts pc 317: / 318: / 319: whead: 320: mov r0,-(sp) 321: mov afout,r0 322: sys seek;0;0 /write pointer to 0 323: sys write;hblk;hsz 324: mov (sp)+,r0 325: rts pc 326: / 327: datasz: 16384. 328: headsz: hsz 329: nbuf: numb 330: nbuf2: numb2 331: 332: b1s: .=.+numb2 333: b1e: .=.+ numb2 334: w1: .=.+ numb2 335: u1: .=.+ numb2 336: b1 = . 337: / 338: initl: 339: mov r0,-(sp) 340: mov r2,-(sp) 341: sys open;asmem; 1 /open for write 342: bec 2f 343: sys creat;asmem; 606 344: bes err2 345: 2: 346: mov r0,afout 347: 1: 348: sys open; asmem; 0 /open for read 349: bes err2 350: mov r0,afi 351: 1: 352: br gargs 353: / 354: err2: 355: mov $1,r0 356: sys write; 1f; 2f-1f 357: 4 358: 1: <cannot open output file\n> 359: 2: 360: asmem: 361: <alloc.d\0> 362: .even 363: / 364: gargs: 365: mov $headers,r2 366: mov r2,r0 367: sub $hblk,r0 368: mov r0,hblk 369: 1: 370: add $8,r0 371: mov r0,(r2) 372: add $8,r2 373: cmp r2,$strend-8. 374: blo 1b 375: clr -8(r2) 376: / 377: mov headsz,datadr 378: add datasz,datadr 379: / 380: mov $frlist,r0 381: 1: clr (r0)+ 382: cmp r0,$frend 383: blo 1b 384: 385: mov hblk,r2 386: add $hblk,r2 387: mov (r2),hblk 388: clr w(r2) 389: mov headsz,a(r2) 390: mov datadr,l(r2) 391: mov datasz,r0 392: jsr pc,log2 393: asl r0 394: cmp r0,$frend-frlist 395: blo 9f; 4; 9: 396: sub $hblk,r2 397: mov r2,frlist(r0) 398: / 399: / install plausible pointers to make octal dumps look ok 400: / 401: mov $hblk,r1 402: 1: mov (r1),r1 403: beq 1f 404: add $hblk,r1 405: mov headsz,a(r1) 406: mov headsz,l(r1) 407: br 1b 408: / 409: 1: mov afout,r0 410: sys write;hblk;hsz 411: jsr pc,reset 412: mov (sp)+,r2 413: mov (sp)+,r0 414: rts pc 415: . = b1 + [512.*numb] 416: / 417: .bss 418: 419: flag: .=.+2 420: stats: .=.+18. 421: useful: .=.+2 422: afi: .=.+2 423: afout: .=.+2 424: datadr: .=.+2 425: hblk: .=.+2 /must remain here - pointer to free header 426: frlist: .=hblk+34. 427: frend: 428: headers: 429: strbuf: .=hblk+hsz 430: strend: 431: nchar: .=.+2 432: end:
Defined functions
b1
declared in line 2; defined in line 336; used 7 times
- in line 2, 415
- in /usr/source/salloc/alloc1.s line 65, 73, 116
- in /usr/source/salloc/alloc2.s line 18, 86
b1e
declared in line 2; defined in line 333; used 5 times
- in line 2
- in /usr/source/salloc/alloc1.s line 189
- in /usr/source/salloc/alloc2.s line 33-34(2), 79
b1s
declared in line 2; defined in line 332; used 8 times
- in line 2
- in /usr/source/salloc/alloc1.s line 188
- in /usr/source/salloc/alloc2.s line 27, 33-37(2), 51, 77-81(2)
u1
declared in line 2; defined in line 335; used 19 times
- in line 2
- in /usr/source/s1/form5.s line 459, 516, 566, 698(2), 724, 736(2)
- in /usr/source/salloc/alloc1.s line 190
- in /usr/source/salloc/alloc2.s line 115(2), 156, 211, 225, 237(2)
- in /usr/source/salloc/altch.s line 9, 57
w1
declared in line 2; defined in line 334; used 9 times
- in line 2
- in /usr/source/salloc/alloc1.s line 111, 187
- in /usr/source/salloc/alloc2.s line 19, 35, 57, 202
- in /usr/source/salloc/altch.s line 9, 47
Defined variables
flag
declared in line 1; defined in line 419; used 16 times
- in line 1
- in /usr/source/s1/form5.s line 454-459(2), 511-516(2), 570, 722
- in /usr/source/salloc/alloc1.s line 194
- in /usr/source/salloc/alloc2.s line 151-156(2), 206-211(2), 223
- in /usr/source/salloc/altch.s line 9, 52-57(2)
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