TI486 Microprocessor - Al Kossow's Bitsavers

More documents

Recommendations

Info

Virtual 8086 Mode 2.9 Virtual 8086 Mode Both Real Mode and Virtual 8086 (V86) Mode are supported by the TI486 CPU allowing execution of 8086 application programs and 8086 operating systems. V86 Mode allows the execution of 8086-type applications, yet still permits use of the TI486 protection mechanism. V86 tasks run at privilege level 3. Upon entry, all segment limits are set to FFFFh (64K) as in real mode. 2.9.1 Memory Addressing While in V86 mode, segment registers are used in an identical fashion to Real Mode. The contents of the segment register are shifted left four bits and added to the offset to form the segment base linear address. The TI486 CPU permits the operating system to select which programs use the V86 address mechanism and which programs use protected mode addressing for each task. The TI486 also permits the use of paging when operating in V86 mode. Using paging, the 1-MByte address space of the V86 task can be mapped to anywhere in the 4-GByte linear address space of the TI486 CPU. As in real mode, linear addresses that exceed 1 MByte cause a segment limit overrun exception. The paging hardware allows multiple V86 tasks to run concurrently, and provides protection and operating system isolation. The paging hardware must be enabled to run multiple V86 tasks or to relocate the address space of a V86 task to physical address space greater than 1 MByte. 2.9.2 Protection All V86 tasks operate with the least amount of privilege (level 3) and are subject to all of the TI486 protected mode protection checks. As a result, any attempt to execute a privileged instruction within a V86 task results in a general protection fault. In V86 mode, a slightly different set of instructions is sensitive to the I/O privilege level (IOPL) than in protected mode. These instructions are: CLI, INT n, IRET, POPF, PUSHF, and STI. The INT3, INTO and BOUND variations of the INT instruction are not 10PL sensitive. 2-61
Virtual 8086 Mode 2.9.3 Interrupt Handling To fully support the emulation of an 8086-type machine, interrupts in V86 mode are handled as follows. When an interrupt or exception is serviced in V86 mode, program execution transfers to the interrupt service routine at privilege level 0 (i.e., transition from V86 to protected mode occurs) and the VM bit in the EFLAGS register is cleared. The protected mode interrupt service routine then determines if the interrupt came from a protected mode or V86 application by examining the VM bit in the EFLAGS image stored on the stack. The interrupt service routine may then choose to allow the 8086 operating system to handle the interrupt or may emulate the function of the interrupt handler. Following completion of the interrupt service routine, an IRET instruction restores the EFLAGS register (restores VM = 1) and segment selectors and control returns to the interrupted V86 task. 2.9.4 Entering and Leaving V86 Mode V86 mode is entered from protected mode either by executing an IRET instruction at CPL = 0 or by task switching. If an IRET is used, the stack must contain an EFLAGS image with VM = 1 . If a task switch is used, the TSS must contain an EFLAGS image containing a 1 in the VM bit position. the POPF instruction cannot be used to enter V86 mode since the state of the VM bit is not affected. V86 mode can be exited only as the result of an interrupt or exception. The transition out must use a 32-bit trap or interrupt gate which must point to a non-conforming privilege level 0 segment (DPL = 0), or a 32-bit TSS. These restrictions are required to permit the trap handler to IRET back to the V86 program. 2-62 Programming Interface
Page 1 and 2:
.TEXAS INSTRUMENTS TI486 Microproce
Page 4 and 5:
TI486 Microprocessor Reference Guid
Page 6 and 7:
Preface Read This First About This
Page 8 and 9:
About This Manual Appendix D Orderi
Page 10 and 11:
Contents 1 Product Overview .......
Page 12 and 13:
Contents 5.5 AC Characteristics . .
Page 14 and 15:
1-1 TI486SLC/E Functional Block Dia
Page 16 and 17:
Figures 4-27 SUSP Initiated Suspend
Page 18 and 19:
Tables 5-3 Absolute Maximum Ratings
Page 20 and 21:
Product Overview 1-1
Page 22 and 23:
Chapter 1 Product Overview Features
Page 24 and 25:
1.2 Differences Between the TI486SL
Page 26 and 27:
Tl486SLCIE Overview Figure 1-2. TI4
Page 28 and 29:
Tl486DLCIE Overview 1.4 TI486DLC/E
Page 30 and 31:
TI486DLCIE Overview The TI486DLC/E
Page 32 and 33:
Power Management / System Managemen
Page 34 and 35:
Programming Interface 2-1
Page 36 and 37:
Chapter 2 In this chapter, the inte
Page 38 and 39:
Processor Initialization Table 2-1.
Page 40 and 41:
Instruction Set Overview 2.2 Instru
Page 42 and 43:
Register Set 2.3 Register Set There
Page 44 and 45: Register Set Pointer and Index Regi
Page 46 and 47: Register Set 2.3.1.2 Segment Regist
Page 48 and 49: Register Set 2.3.1.3 Instruction Po
Page 50 and 51: Register Set 2.3.2 System Register
Page 52 and 53: Register Set 2.3.2.1 Control Regist
Page 54 and 55: Register Set 2.3.2.2 Descriptor Tab
Page 56 and 57: Register Set Table 2-6. Segment Des
Page 58 and 59: Register Set During task switching,
Page 60 and 61: Register Set The CCRO register (Tab
Page 62 and 63: Register Set Table 2-9. TI486DLCIE
Page 64 and 65: Register Set Table 2-12. ARR 1-ARR4
Page 66 and 67: Register Set 2.3.2.6 Test Registers
Page 68 and 69: Register Set Table 2-14. TR6 and TR
Page 70 and 71: Address Spaces 2.4 Address Spaces T
Page 72 and 73: Address Spaces 2.4.2 Memory Address
Page 74 and 75: Address Spaces Figure 2-21. Real Mo
Page 76 and 77: Address Spaces Figure 2-24. Paging
Page 78 and 79: Interrupts and Exceptions 2.5 Inter
Page 80 and 81: Interrupts and Exceptions 2.5.3 Int
Page 82 and 83: Interrupts and Exceptions Table 2-2
Page 84 and 85: System Management Mode 2.6 System M
Page 86 and 87: System Management Mode Figure 2-29.
Page 88 and 89: System Management Mode The new SMM
Page 90 and 91: System Management Mode During SMM o
Page 92 and 93: Protection The Current Privilege Le
Page 96 and 97: TI486SLC/E Bus Interface 3-1
Page 98 and 99: Chapter 3 TI486SLC/E Bus Interface
Page 100 and 101: Overview Table 3-1. TI486SLCIE Sign
Page 102 and 103: Overview Table 3-2. Terminal Functi
Page 108 and 109: Overview 3.1.1 Bus Cycle Definition
Page 110 and 111: Overview Table 3-5 shows the state
Page 112 and 113: Functional Timing Figure 3-3. Bus A
Page 114 and 115: Functional Timing 3.2.2.1 Bus Cycle
Page 116 and 117: Functional Timing Non-Pipelined Wai
Page 118 and 119: Functional Timing Because of the de
Page 120 and 121: Functional Timing Pipelined Wait St
Page 122 and 123: Functional Timing Initiating and Ma
Page 124 and 125: Functional Timing Figure 3-12. Comp
Page 126 and 127: Functional Timing Figure 3-13. Inte
Page 128 and 129: Functional Timing Shutdown Indicati
Page 130 and 131: Functional Timing Figure 3-17. Pipe
Page 132 and 133: Functional Timing As shown in Figur
Page 134 and 135: Functional Timing Figure 3-19. Requ
Page 136 and 137: Functional Timing Figure 3-21. Requ
Page 138 and 139: Functional Timing Figure 3-22. 8MI
Page 140 and 141: Functional Timing HALT Initiated Su
Page 142 and 143: Functional Timing 3.2.12 Float Figu
Page 144 and 145:
TI486DLC/E Bus Interface 4-1
Page 146 and 147:
Chapter 4 TI486DLC/E Bus Interface
Page 148 and 149:
Overview Table 4-1. TI486DLCIE SIgn
Page 150 and 151:
Overview Table 4-2. Terminal Functi
Page 152 and 153:
Page 154 and 155:
Page 156 and 157:
Overview Table 4-6. Signal States D
Page 158 and 159:
Overview 4.1.2 Power Management 4.1
Page 160 and 161:
Functional Timing 4.2 Functional Ti
Page 162 and 163:
Functional Timing The TI486DLC/E da
Page 164 and 165:
Functional Timing Non-Pipelined Rea
Page 166 and 167:
Functional Timing Initiating and Ma
Page 168 and 169:
Functional Timing Figure 4-8. Faste
Page 170 and 171:
Functional Timing Figure 4-9. Vario
Page 172 and 173:
Functional Timing Once a pipelined
Page 174 and 175:
Functional Timing 4.2.3 Bus Cycles
Page 176 and 177:
Functional Timing Pipelined Cycles
Page 178 and 179:
Functional Timing LOCK is activated
Page 180 and 181:
Functional Timing 4.2.6 Halt and Sh
Page 182 and 183:
Functional Timing Figure 4-17. Pipe
Page 184 and 185:
Functional Timing Figure 4-19. Non-
Page 186 and 187:
Functional Timing The TI486DLC/E sa
Page 188 and 189:
Functional Timing 4.2.9 Hold Acknow
Page 190 and 191:
Functional Timing Figure 4-23. Requ
Page 192 and 193:
Functional Timing 4.2.10 Coprocesso
Page 194 and 195:
Functional Timing 4.2.12 Power Mana
Page 196 and 197:
Functional Timing Stopping the Inpu
Page 198 and 199:
Electrical Specifications 5-1
Page 200 and 201:
Chapter 5 Electrical Specifications
Page 202 and 203:
ElectricalConnecnons It is recommen
Page 204 and 205:
Recommended Operating Conditions 5.
Page 206 and 207:
DC Electrical Characteristics Table
Page 208 and 209:
AC Characteristics Figure 5-2. TI48
Page 210 and 211:
AC Characteristics Table 5-9. AC Ch
Page 212 and 213:
AC Characteristics Table 5-11. AC C
Page 214 and 215:
____ AC Characteristics 5.5.3 RESET
Page 216 and 217:
Page 218 and 219:
Page 220 and 221:
Mechanical Specifications 6-1
Page 222 and 223:
Chapter 6 Mechanical Specifications
Page 224 and 225:
Pin Assignments Table 6-1. TI486SLC
Page 226 and 227:
Pin Assignments Figure 6-3. TI486DL
Page 228 and 229:
Package Dimensions 6.2 Package Dime
Page 230 and 231:
Thermal Characteristics 6.3 Thermal
Page 232 and 233:
Instruction Set 7-1
Page 234 and 235:
Chapter 7 Instruction Set This sect
Page 236 and 237:
Instruction Fields 7.2 Instruction
Page 238 and 239:
Instruction Fields 7.2.5 reg Field
Page 240 and 241:
Instruction Fields Table 7-7. mod r
Page 242 and 243:
Instruction Fields 7.2.11 sreg3 Fie
Page 244 and 245:
Clock Count Summary 7.4 Clock Count
Page 246 and 247:
--- --;.J -L 01 Table 7-17. Instruc
Page 248 and 249:
I . ~ -.....J Table 7-17. Instructi
Page 250 and 251:
Table 7-17. Instructions, Opcodes,
Page 252 and 253:
Page 254 and 255:
-....J N (J.) Table 7-17. Instructi
Page 256 and 257:
I I i I i Table 7-17. Instructions,
Page 258 and 259:
...... ...... '" Table 7-17. Instru
Page 260 and 261:
-....J N co Table 7-17. Instruction
Page 262 and 263:
"-.I ~ Table 7-17. Instructions, Op
Page 264 and 265:
Page 266 and 267:
U Appendix A TI486 SMM Pro rammer's
Page 268 and 269:
SMM Implementation A.2 SMM Implemen
Page 270 and 271:
Figure A-1. SMM Memory Space Header
Page 272 and 273:
SMM Implementation 6) NMI is the on
Page 274 and 275:
Instruction Summary A.4 Instruction
Page 276 and 277:
Instruction Summary A.4.3 Resume No
Page 278 and 279:
Instruction Summary A.4.6 Save LDTR
Page 280 and 281:
8MI Handler Example A.5 SMI Handler
Page 282 and 283:
8MI Handler Example execute_halt: C
Page 284 and 285:
8MI Handler Example COMMENT A The T
Page 286 and 287:
8MI Handler Example arrl arr2 arr3
Page 288 and 289:
.MODEL SMALL . STACK .386P INCLUDE
Page 290 and 291:
Testing/Debugging SMM Code sgdt COM
Page 292 and 293:
Testing/Debugging SMM Code i*******
Page 294 and 295:
TI486 Power Management Features A.7
Page 296 and 297:
Detection of Tl486 CPU A.9 Detectio
Page 298 and 299:
Detection of SMM Capable Version A.
Page 300 and 301:
i**********************************
Page 302 and 303:
A.11 SMM Feature Comparison SMM Fea
Page 304 and 305:
SMM Instruction Macros COMMENT A Co
Page 306 and 307:
SMM Instruction Macros SMM Instruct
Page 308 and 309:
A.14 Format of Data Used by SVDC/RS
Page 310 and 311:
Altering SMM Code Limits A.1S Alter
Page 312 and 313:
SMM Errata A.16 SMM Errata The foll
Page 314 and 315:
Appendix B TI486 Cache Flush B.1 Ge
Page 316 and 317:
Appendix C TI486 BIOS Modification
Page 318 and 319:
Introduction Some example assembler
Page 320 and 321:
Appendix D Ordering Information 0.1
Page 322:
~TEXAS INSTRUMENTS Printed in U.S.A
show all

TI486 Microprocessor - Al Kossow's Bitsavers

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?