mirror of
https://github.com/holub/mame
synced 2025-05-29 17:13:05 +03:00
i386: Made a start at Virtual 8086 Mode. Not fully working yet, though.
Fixed an issue where two address or operand size prefixes would cancel
each other out.
This commit is contained in:
mahlemiut
parent
5e0e5c8bc7
commit
44ee92ea77
@ -167,6 +167,7 @@ static UINT32 get_flags(i386_state *cpustate)
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f |= cpustate->IOP1 << 12;
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f |= cpustate->IOP2 << 13;
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f |= cpustate->NT << 14;
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f |= cpustate->VM << 17;
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return (cpustate->eflags & cpustate->eflags_mask) | (f & 0xffff);
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}
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@ -184,6 +185,7 @@ static void set_flags(i386_state *cpustate, UINT32 f )
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cpustate->IOP1 = (f & 0x1000) ? 1 : 0;
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cpustate->IOP2 = (f & 0x2000) ? 1 : 0;
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cpustate->NT = (f & 0x4000) ? 1 : 0;
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cpustate->VM = (f & 0x20000) ? 1 : 0;
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cpustate->eflags = f & cpustate->eflags_mask;
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}
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@ -575,13 +577,13 @@ static void i386_trap(i386_state *cpustate,int irq, int irq_gate, int trap_level
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/* segment privilege checks */
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if(entry > cpustate->idtr.limit)
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{
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logerror("IRQ: Vector is past IDT limit.\n");
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logerror("IRQ (%08x): Vector %02xh is past IDT limit.\n",cpustate->pc,entry);
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FAULT_EXP(FAULT_GP,entry+2)
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}
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/* segment must be interrupt gate, trap gate, or task gate */
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if(type != 0x05 && type != 0x06 && type != 0x07 && type != 0x0e && type != 0x0f)
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{
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logerror("IRQ: Vector segment is not an interrupt, trap or task gate.\n");
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logerror("IRQ (%08x): Vector segment %04x is not an interrupt, trap or task gate.\n",cpustate->pc,segment);
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FAULT_EXP(FAULT_GP,entry+2)
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}
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@ -593,6 +595,48 @@ static void i386_trap(i386_state *cpustate,int irq, int irq_gate, int trap_level
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FAULT_EXP(FAULT_NP,entry+2)
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}
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if(V8086_MODE)
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{
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UINT32 tempflags;
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UINT32 tempESP,tempSS;
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/* Interrupt for a Virtual 8086 task */
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logerror("IRQ (%08x): Interrupt during V8086 task\n",cpustate->pc);
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tempflags = get_flags(cpustate);
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cpustate->VM = 0;
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cpustate->TF = 0;
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if(irq_gate == 1)
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cpustate->IF = 0;
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tempSS = cpustate->sreg[SS].selector;
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tempESP = REG32(ESP);
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/* Get privilege level 0 stack pointer from TSS */
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cpustate->sreg[SS].selector = i386_get_stack_segment(cpustate,0);
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REG32(ESP) = i386_get_stack_ptr(cpustate,0);
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PUSH32(cpustate,cpustate->sreg[GS].selector & 0xffff);
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PUSH32(cpustate,cpustate->sreg[FS].selector & 0xffff);
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PUSH32(cpustate,cpustate->sreg[DS].selector & 0xffff);
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PUSH32(cpustate,cpustate->sreg[ES].selector & 0xffff);
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cpustate->sreg[GS].selector = 0;
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cpustate->sreg[FS].selector = 0;
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cpustate->sreg[DS].selector = 0;
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cpustate->sreg[ES].selector = 0;
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i386_load_segment_descriptor(cpustate,GS);
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i386_load_segment_descriptor(cpustate,FS);
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i386_load_segment_descriptor(cpustate,DS);
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i386_load_segment_descriptor(cpustate,ES);
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PUSH32(cpustate,tempESP);
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PUSH32(cpustate,tempSS & 0xffff);
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PUSH32(cpustate,tempflags);
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PUSH32(cpustate,cpustate->sreg[CS].selector & 0xffff);
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PUSH32(cpustate,cpustate->eip);
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cpustate->sreg[CS].selector = segment;
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cpustate->eip = offset;
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i386_load_segment_descriptor(cpustate,CS);
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CHANGE_PC(cpustate,cpustate->eip);
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return;
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}
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if(type == 0x05)
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{
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/* Task gate */
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@ -1428,7 +1472,7 @@ static void i386_protected_mode_call(i386_state *cpustate, UINT16 seg, UINT32 of
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}
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if((desc.flags & 0x0080) == 0)
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{
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logerror("CALL: Code segment is not present.\n");
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logerror("CALL (%08x): Code segment is not present.\n",cpustate->pc);
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FAULT(FAULT_NP,selector & ~0x07) // #NP(selector)
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}
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if (operand32 != 0) // if 32-bit
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@ -2032,6 +2076,11 @@ static void i386_protected_mode_retf(i386_state* cpustate, UINT8 count, UINT8 op
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}
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cpustate->CPL = newCS & 0x03;
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if(operand32 == 0)
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REG16(SP) += (8+count);
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else
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REG32(ESP) += (16+count);
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/* Load new SS:(E)SP */
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if(operand32 == 0)
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REG16(SP) = newESP & 0xffff;
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@ -2040,12 +2089,6 @@ static void i386_protected_mode_retf(i386_state* cpustate, UINT8 count, UINT8 op
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cpustate->sreg[SS].selector = newSS;
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i386_load_segment_descriptor(cpustate, SS );
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if(operand32 == 0)
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REG16(SP) += (8+count);
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else
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REG32(ESP) += (16+count);
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/* Check that DS, ES, FS and GS are valid for the new privilege level */
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i386_check_sreg_validity(cpustate,DS);
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i386_check_sreg_validity(cpustate,ES);
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@ -2067,7 +2110,7 @@ static void i386_protected_mode_iret(i386_state* cpustate, int operand32)
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{
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UINT32 newCS, newEIP;
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UINT32 newSS, newESP; // when changing privilege
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I386_SREG desc;
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I386_SREG desc,stack;
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UINT8 CPL, RPL, DPL;
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UINT32 newflags;
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@ -2093,8 +2136,28 @@ static void i386_protected_mode_iret(i386_state* cpustate, int operand32)
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if(V8086_MODE)
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{
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logerror("IRET: Is in Virtual 8086 mode.\n");
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FAULT(FAULT_GP,0)
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if(!cpustate->IOP1 || !cpustate->IOP2)
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{
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logerror("IRET: Is in Virtual 8086 mode and IOPL != 3.\n");
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FAULT(FAULT_GP,0)
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}
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/* Is this correct? The 80386 programmers' reference says IRET should always trigger #GP(0) in V86 mode */
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if(operand32 == 0)
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{
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cpustate->eip = newEIP & 0xffff;
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cpustate->sreg[CS].selector = newCS & 0xffff;
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newflags |= 0x3000; // IOPL cannot be changed in V86 mode
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newflags |= 0x4000; // NT flag
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set_flags(cpustate,newflags & 0xffff);
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}
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else
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{
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cpustate->eip = newEIP;
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cpustate->sreg[CS].selector = newCS & 0xffff;
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newflags |= 0x3000; // IOPL cannot be changed in V86 mode
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newflags |= 0x4000; // NT flag
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set_flags(cpustate,newflags & 0xffff);
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}
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}
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else if(NESTED_TASK)
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{
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@ -2135,8 +2198,149 @@ static void i386_protected_mode_iret(i386_state* cpustate, int operand32)
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{
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if(newflags & 0x00020000) // if returning to virtual 8086 mode
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{
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UINT8 SSRPL,SSDPL;
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memset(&desc, 0, sizeof(desc));
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desc.selector = newCS;
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i386_load_protected_mode_segment(cpustate,&desc);
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DPL = (desc.flags >> 5) & 0x03; // descriptor privilege level
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RPL = newCS & 0x03;
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memset(&stack, 0, sizeof(stack));
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stack.selector = newSS;
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i386_load_protected_mode_segment(cpustate,&stack);
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SSRPL = newSS & 0x03;
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SSDPL = (stack.flags >> 5) & 0x03;
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/* Return to v86 mode */
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popmessage("IRET (%08x): Unimplemented return to Virtual 8086 mode.",cpustate->pc);
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popmessage("IRET (%08x): Returning to Virtual 8086 mode.",cpustate->pc);
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// Should these be done at this point? The 386 programmers' reference is a bit confusing about this
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/* if(RPL != 3)
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{
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logerror("IRET to V86 (%08x): Return CS RPL is not 3\n",cpustate->pc);
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FAULT(FAULT_GP,newCS);
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}
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if(operand32 == 0)
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{
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if(REG16(SP)+36 > cpustate->sreg[SS].limit)
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{
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logerror("IRET to V86 (%08x): Stack does not have enough room left\n",cpustate->pc);
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FAULT(FAULT_SS,0);
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}
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}
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else
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{
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if(REG32(ESP)+36 > cpustate->sreg[SS].limit)
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{
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logerror("IRET to V86 (%08x): Stack does not have enough space left\n",cpustate->pc);
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FAULT(FAULT_SS,0);
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}
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}
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// code segment checks
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if((newCS & ~0x07) == 0)
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{
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logerror("IRET to V86 (%08x): Return CS selector is null\n",cpustate->pc);
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FAULT(FAULT_GP,newCS);
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}
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if(desc.flags & 0x04)
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{ // LDT
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if(newCS > cpustate->ldtr.limit)
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{
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logerror("IRET to V86 (%08x): Return CS selector is past LDT limit\n",cpustate->pc);
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FAULT(FAULT_GP,newCS);
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}
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}
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else
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{ // GDT
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if(newCS > cpustate->gdtr.limit)
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{
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logerror("IRET to V86 (%08x): Return CS selector is past GDT limit\n",cpustate->pc);
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FAULT(FAULT_GP,newCS);
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}
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}
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if((desc.flags & 0x18) != 0x18)
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{
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logerror("IRET to V86 (%08x): Return CS segment is not a code segment\n",cpustate->pc);
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FAULT(FAULT_GP,newCS);
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}
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if(DPL != 3)
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{
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logerror("IRET to V86 (%08x): Return CS segment does not have a DPL of 3\n",cpustate->pc);
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FAULT(FAULT_GP,newCS);
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}
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if(!(desc.flags & 0x0080))
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{
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logerror("IRET to V86 (%08x): Return CS segment is not present\n",cpustate->pc);
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FAULT(FAULT_NP,newCS);
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}
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// Stack segment checks
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if((newSS & ~0x07) == 0)
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{
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logerror("IRET to V86 (%08x): Return SS segment is null\n",cpustate->pc);
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FAULT(FAULT_GP,newSS);
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}
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if(desc.flags & 0x04)
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{ // LDT
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if(newSS > cpustate->ldtr.limit)
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{
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logerror("IRET to V86 (%08x): Return SS selector is past LDT limit\n",cpustate->pc);
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FAULT(FAULT_GP,newSS);
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}
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}
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else
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{ // GDT
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if(newSS > cpustate->gdtr.limit)
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{
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logerror("IRET to V86 (%08x): Return SS selector is past GDT limit\n",cpustate->pc);
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FAULT(FAULT_GP,newSS);
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}
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}
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if(SSRPL != RPL)
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{
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logerror("IRET to V86 (%08x): Return SS selector RPL is not equal to CS selector RPL\n",cpustate->pc);
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FAULT(FAULT_GP,newSS);
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}
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if(((stack.flags & 0x0018) != 0x10) && (!(stack.flags & 0x02)))
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{
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logerror("IRET to V86 (%08x): Return SS segment is not a writable data segment\n",cpustate->pc);
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FAULT(FAULT_GP,newSS);
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}
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if(SSDPL != RPL)
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{
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logerror("IRET to V86 (%08x): Return SS segment DPL is not equal to CS selector RPL\n",cpustate->pc);
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FAULT(FAULT_GP,newSS);
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}
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if(!(stack.flags & 0x0080))
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{
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logerror("IRET to V86 (%08x): Return SS segment is not present\n",cpustate->pc);
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FAULT(FAULT_NP,newSS);
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}
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if(newEIP > desc.limit)
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{
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logerror("IRET to V86 (%08x): New EIP is past CS segment limit\n",cpustate->pc);
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FAULT(FAULT_GP,0);
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}
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*/
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set_flags(cpustate,newflags);
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cpustate->eip = POP32(cpustate) & 0xffff; // high 16 bits are ignored
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cpustate->sreg[CS].selector = POP32(cpustate) & 0xffff;
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POP32(cpustate); // already set flags
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if(RPL > CPL)
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{
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newESP = POP32(cpustate);
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newSS = POP32(cpustate) & 0xffff;
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}
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cpustate->sreg[ES].selector = POP32(cpustate) & 0xffff;
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cpustate->sreg[DS].selector = POP32(cpustate) & 0xffff;
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cpustate->sreg[FS].selector = POP32(cpustate) & 0xffff;
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cpustate->sreg[GS].selector = POP32(cpustate) & 0xffff;
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REG32(ESP) = newESP; // all 32 bits are loaded
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cpustate->sreg[SS].selector = newSS;
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i386_load_segment_descriptor(cpustate,ES);
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i386_load_segment_descriptor(cpustate,DS);
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i386_load_segment_descriptor(cpustate,FS);
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i386_load_segment_descriptor(cpustate,GS);
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i386_load_segment_descriptor(cpustate,SS);
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cpustate->CPL = 3; // Virtual 8086 tasks are always run at CPL 3
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}
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else
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{
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@ -2383,10 +2587,10 @@ static void i386_protected_mode_iret(i386_state* cpustate, int operand32)
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FAULT(FAULT_GP,0)
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}
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if(operand32 == 0)
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REG16(SP) += 10;
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else
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REG32(ESP) += 20;
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// if(operand32 == 0)
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// REG16(SP) += 10;
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// else
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// REG32(ESP) += 20;
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if(operand32 == 0)
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{
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@ -2790,6 +2994,8 @@ static CPU_EXECUTE( i386 )
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{
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cpustate->operand_size = cpustate->sreg[CS].d;
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cpustate->address_size = cpustate->sreg[CS].d;
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cpustate->operand_prefix = 0;
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cpustate->address_prefix = 0;
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cpustate->segment_prefix = 0;
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cpustate->prev_eip = cpustate->eip;
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@ -1092,6 +1092,8 @@ static const char *const i386_sreg[8] = {"es", "cs", "ss", "ds", "fs", "gs", "??
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static int address_size;
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static int operand_size;
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static int address_prefix;
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static int operand_prefix;
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static int max_length;
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static UINT64 pc;
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static UINT8 modrm;
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@ -2021,18 +2023,25 @@ static void decode_opcode(char *s, const I386_OPCODE *op, UINT8 op1)
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case OP_SIZE:
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rex = regex = sibex = rmex = 0;
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if (operand_size < 2)
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if (operand_size < 2 && operand_prefix == 0)
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{
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operand_size ^= 1;
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operand_prefix = 1;
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}
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op2 = FETCH();
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decode_opcode( s, &i386_opcode_table1[op2], op2 );
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return;
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case ADDR_SIZE:
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rex = regex = sibex = rmex = 0;
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if (curmode != 64)
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address_size ^= 1;
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else
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address_size ^= 3;
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if(address_prefix == 0)
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{
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if (curmode != 64)
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address_size ^= 1;
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else
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address_size ^= 3;
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address_prefix = 1;
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}
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op2 = FETCH();
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decode_opcode( s, &i386_opcode_table1[op2], op2 );
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return;
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@ -2163,6 +2172,8 @@ int i386_dasm_one_ex(char *buffer, UINT64 eip, const UINT8 *oprom, int mode)
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curmode = mode;
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pre0f = 0;
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rex = regex = sibex = rmex = 0;
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address_prefix = 0;
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operand_prefix = 0;
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op = FETCH();
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@ -3330,7 +3330,7 @@ static void I386OP(lsl_r16_rm16)(i386_state *cpustate) // Opcode 0x0f 0x03
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UINT32 limit;
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I386_SREG seg;
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if(PROTECTED_MODE)
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if(PROTECTED_MODE && !V8086_MODE)
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{
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memset(&seg, 0, sizeof(seg));
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if(modrm >= 0xc0)
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@ -3147,7 +3147,7 @@ static void I386OP(lsl_r32_rm32)(i386_state *cpustate) // Opcode 0x0f 0x03
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UINT32 limit;
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I386_SREG seg;
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if(PROTECTED_MODE)
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if(PROTECTED_MODE && !V8086_MODE)
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{
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memset(&seg, 0, sizeof(seg));
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if(modrm >= 0xc0)
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@ -2207,13 +2207,21 @@ static void I386OP(segment_SS)(i386_state *cpustate) // Opcode 0x36
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static void I386OP(operand_size)(i386_state *cpustate) // Opcode 0x66
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{
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cpustate->operand_size ^= 1;
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if(cpustate->operand_prefix == 0)
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{
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cpustate->operand_size ^= 1;
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cpustate->operand_prefix = 1;
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}
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I386OP(decode_opcode)(cpustate);
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}
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static void I386OP(address_size)(i386_state *cpustate) // Opcode 0x67
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{
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cpustate->address_size ^= 1;
|
||||
if(cpustate->address_prefix == 0)
|
||||
{
|
||||
cpustate->address_size ^= 1;
|
||||
cpustate->address_prefix = 1;
|
||||
}
|
||||
I386OP(decode_opcode)(cpustate);
|
||||
}
|
||||
|
||||
|
||||
@ -225,6 +225,7 @@ struct _i386_state
|
||||
UINT8 IOP1;
|
||||
UINT8 IOP2;
|
||||
UINT8 NT;
|
||||
UINT8 VM;
|
||||
|
||||
UINT8 CPL; // current privilege level
|
||||
|
||||
@ -244,6 +245,8 @@ struct _i386_state
|
||||
|
||||
int operand_size;
|
||||
int address_size;
|
||||
int operand_prefix;
|
||||
int address_prefix;
|
||||
|
||||
int segment_prefix;
|
||||
int segment_override;
|
||||
|
||||
Loading…
Reference in New Issue
Block a user