Compile subtraction of immediates

mehfooz09 · May 8, 2018 · d91e7b7 · d91e7b7
1 parent 540d363
commit d91e7b7
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Showing 5 changed files with 41 additions and 35 deletions.
diff --git a/emu/gadgets-x86/gadgets.S b/emu/gadgets-x86/gadgets.S
@@ -43,7 +43,7 @@ jit_exit:
     ret
 
 .gadget interrupt
-    op %tmp
+    movl (%ip), %tmp
     jmp jit_exit
 
 .gadget exit
@@ -58,14 +58,14 @@ jit_exit:
 
 .macro mem_\type place
     movl %addr, %r14d
-    shll $8, %r14d
+    shrl $8, %r14d
     andl $0x3ff0, %r14d
-    movl %addr, %tmp
-    andl $0xfffff000, %tmp
+    movl %addr, %r15d
+    andl $0xfffff000, %r15d
     .ifc \type,read
-        cmpl TLB_ENTRY_page(%tlb,%r14), %tmp
+        cmpl TLB_ENTRY_page(%tlb,%r14), %r15d
     .else
-        cmpl TLB_ENTRY_page_if_writable(%tlb,%r14), %tmp
+        cmpl TLB_ENTRY_page_if_writable(%tlb,%r14), %r15d
     .endif
     je 1f
     call handle_\type\()_miss
@@ -122,7 +122,7 @@ segfault:
 .type \type\()_gadgets,@object
 \type\()_gadgets:
     # The following .irp should stay in sync with enum arg in emu/gen.c
-    .irp arg, eax,ecx,edx,ebx,esp,ebp,esi,edi,ax,cx,dx,bx,sp,bp,si,di,mem32
+    .irp arg, eax,ecx,edx,ebx,esp,ebp,esi,edi,ax,cx,dx,bx,sp,bp,si,di,imm,mem32
         .ifndef gadget_\type\()_\arg
             .set gadget_\type\()_\arg, 0
         .endif
@@ -131,9 +131,9 @@ segfault:
 .endm
 
 .gadget push
+    sub $4, %xsp
     movl %xsp, %addr
     mem_write %tmp
-    sub $4, %xsp
     gret
 .gadget pop
     movl %xsp, %addr
@@ -150,6 +150,11 @@ segfault:
 .endm
 .reg_gadgets store
 
+.gadget sub_imm
+    subl (%ip), %tmp
+    gret 1
+
 .data
 .gadget_array load
 .gadget_array store
+.gadget_array sub
diff --git a/emu/gadgets-x86/gadgets.h b/emu/gadgets-x86/gadgets.h
@@ -11,16 +11,11 @@
     .global gadget_\()\name
     gadget_\()\name :
 .endm
-.macro gret
-    addq $8, %ip
+.macro gret pop=0
+    addq $((\pop+1)*8), %ip
     jmp *-8(%ip)
 .endm
 
-.macro op reg
-    mov (%ip), \reg
-    addq $8, %ip
-.endm
-
 # using a gas macro for this works fine on gcc but not on clang
 #define each_reg irp reg, eax,ecx,edx,ebx,ebp,esp,esi,edi
 

diff --git a/emu/gen.c b/emu/gen.c
@@ -1,3 +1,4 @@
+#include <assert.h>
 #include "emu/modrm.h"
 #include "emu/gen.h"
 #include "emu/interrupt.h"
@@ -6,11 +7,11 @@
 enum arg {
     arg_eax, arg_ecx, arg_edx, arg_ebx, arg_esp, arg_ebp, arg_esi, arg_edi,
     arg_ax, arg_cx, arg_dx, arg_bx, arg_sp, arg_bp, arg_si, arg_di,
-    arg_mem32,
+    arg_imm, arg_mem32,
     arg_cnt,
     // the following should not be synced with the aforementioned .irp (no gadgets implement them)
     arg_al, arg_cl, arg_dl, arg_bl, arg_ah, arg_ch, arg_dh, arg_bh,
-    arg_modrm_val, arg_modrm_reg, arg_mem_addr, arg_imm, arg_addr, arg_gs,
+    arg_modrm_val, arg_modrm_reg, arg_mem_addr, arg_addr, arg_gs,
     // markers
     arg_reg32 = arg_eax, arg_reg16 = arg_ax,
 };
@@ -22,33 +23,39 @@ void gadget_exit();
 void gadget_push();
 extern gadget_t load_gadgets[arg_cnt];
 extern gadget_t store_gadgets[arg_cnt];
+extern gadget_t sub_gadgets[arg_cnt];
 
 #define GEN(thing) gen(state, (unsigned long) (thing))
-#define G(g) GEN(gadget_##g)
-#define GG(g, a) do { GEN(gadget_##g); GEN(a); } while(0)
-#define UNDEFINED GG(interrupt, INT_UNDEFINED); return
+#define g(g) GEN(gadget_##g)
+#define gg(g, a) do { GEN(gadget_##g); GEN(a); } while (0)
+#define UNDEFINED do { gg(interrupt, INT_UNDEFINED); return; } while (0)
 
-static inline void gen_op(struct gen_state *state, gadget_t *gadgets, enum arg arg, struct modrm *modrm) {
+static inline void gen_op(struct gen_state *state, gadget_t *gadgets, enum arg arg, struct modrm *modrm, uint64_t *imm) {
     switch (arg) {
-        case arg_eax ... arg_edi:
-            GEN(gadgets[arg]); break;
         case arg_modrm_reg:
             // TODO find some way to assert that this won't overflow?
-            GEN(gadgets[modrm->reg + arg_reg32]); break;
+            arg = modrm->reg + arg_reg32; break;
         case arg_modrm_val:
             switch (modrm->type) {
                 case modrm_reg:
-                    GEN(gadgets[modrm->base + arg_reg32]); break;
+                    arg = modrm->base + arg_reg32; break;
                 default: UNDEFINED;
             }
             break;
-        default: UNDEFINED;
+        default: break;
     }
+    if (arg >= arg_cnt || gadgets[arg] == NULL) {
+        debugger;
+        UNDEFINED;
+    }
+    GEN(gadgets[arg]);
+    if (arg == arg_imm)
+        GEN(*imm);
 }
-#define GEN_OP(type, thing) gen_op(state, type##_gadgets, arg_##thing, &modrm)
+#define op(type, thing) gen_op(state, type##_gadgets, arg_##thing, &modrm, &imm)
 
-#define load(thing) GEN_OP(load, thing)
-#define store(thing) GEN_OP(store, thing)
+#define load(thing) op(load, thing)
+#define store(thing) op(store, thing)
 
 #define DECLARE_LOCALS \
     dword_t addr_offset = 0;
@@ -74,15 +81,15 @@ static inline void gen_op(struct gen_state *state, gadget_t *gadgets, enum arg a
 #define ADC(src, dst,z) UNDEFINED
 #define SBB(src, dst,z) UNDEFINED
 #define AND(src, dst,z) UNDEFINED
-#define SUB(src, dst,z) UNDEFINED
+#define SUB(src, dst,z) load(dst); op(sub, src); store(dst)
 #define XOR(src, dst,z) UNDEFINED
 #define CMP(src, dst,z) UNDEFINED
 #define TEST(src, dst,z) UNDEFINED
 #define NOT(val,z) UNDEFINED
 #define NEG(val,z) UNDEFINED
 
 #define POP(thing) UNDEFINED
-#define PUSH(thing) load(thing); G(push)
+#define PUSH(thing) load(thing); g(push)
 
 #define INC(val,z) UNDEFINED
 #define DEC(val,z) UNDEFINED

diff --git a/emu/interp.c b/emu/interp.c
@@ -106,7 +106,6 @@ static bool modrm_compute(struct cpu_state *cpu, struct tlb *tlb, addr_t *addr_o
     }(void)0
 
 #define get_imm(size) ((uint(size)) imm)
-#define get_imm8(size) ((int8_t) (uint8_t) imm)
 
 #define get_mem_addr(size) mem_read(addr, size)
 #define set_mem_addr(to, size) mem_write(addr, to, size)
@@ -423,7 +422,7 @@ static bool modrm_compute(struct cpu_state *cpu, struct tlb *tlb, addr_t *addr_o
     switch (modrm.opcode) { \
         case 0: \
         case 1: TRACE("test imm"); \
-                READIMM8; TEST(imm8, val); break; \
+                READIMM8; TEST(imm, val); break; \
         case 2: TRACE("not"); return INT_UNDEFINED; \
         case 3: TRACE("neg"); return INT_UNDEFINED; \
         case 4: TRACE("mul"); return INT_UNDEFINED; \

diff --git a/emu/interp/sse.h b/emu/interp/sse.h
@@ -14,8 +14,8 @@
     dst >>= count
 #define PSRLQ(count, dst) \
     xmm_dst = get(dst,128); \
-    SRL(get(count,z), xmm_dst.qw[0]); \
-    SRL(get(count,z), xmm_dst.qw[1]); \
+    SRL(get(count,), xmm_dst.qw[0]); \
+    SRL(get(count,), xmm_dst.qw[1]); \
     set(dst, xmm_dst,128)
 
 #define XORP(src, dst) \