diff --git a/examples/sysir/typeerr0.janet b/examples/sysir/typeerr0.janet
deleted file mode 100644
index 581d885f..00000000
--- a/examples/sysir/typeerr0.janet
+++ /dev/null
@@ -1,55 +0,0 @@
-### typedef struct {float x; float y; float z;} Vec3;
-###
-### Vec3 addv(Vec3 a, Vec3 b) {
-###     Vec3 ret;
-###     ret.x = a.x + b.x;
-###     ret.y = a.y + b.y;
-###     ret.z = a.z + b.z;
-###     return ret;
-### }
-
-(def ir-asm
-  '((link-name "addv_with_err")
-    (parameter-count 2)
-    # Types
-    (type-prim Real f32)
-    (type-struct Vec3 Real Real Real)
-    (type-pointer PReal Real)
-
-    # Declarations
-    (bind position Vec3)
-    (bind velocity Vec3)
-    (bind next-position Vec3)
-    (bind dest Real)
-    (bind lhs Real)
-    (bind rhs Real)
-    (bind pdest PReal)
-    (bind plhs PReal)
-    (bind prhs PReal)
-
-    # Code (has type errors)
-    (fgetp pdest next-position 0)
-    (fgetp plhs position 0)
-    (fgetp prhs velocity 0)
-    (add dest plhs prhs)
-    (store pdest dest)
-
-    (fgetp pdest next-position 1)
-    (fgetp plhs position 1)
-    (fgetp prhs velocity 1)
-    (add dest lhs rhs)
-    (load lhs plhs)
-    (load rhs prhs)
-    (store pdest dest)
-
-    (fgetp pdest next-position 2)
-    (fgetp plhs position 2)
-    (fgetp prhs velocity 2)
-    (add dest plhs prhs)
-    (store pdest dest)
-
-    (return next-position)))
-
-(def ctx (sysir/context))
-(sysir/asm ctx ir-asm)
-(print (sysir/to-c ctx))
diff --git a/src/core/sysir_x86.c b/src/core/sysir_x86.c
index a8da07f1..73f1d944 100644
--- a/src/core/sysir_x86.c
+++ b/src/core/sysir_x86.c
@@ -52,31 +52,6 @@
 #define REX_X 0x42
 #define REX_B 0x41
 
-static const char *register_names[] = {
-    "rax", "rcx", "rdx", "rbx", "rsp", "rbp", "rsi", "rdi",
-    "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15"
-};
-
-static const char *register_names_32[] = {
-    "eax", "ecx", "edx", "ebx", "rsp", "rbp", "esi", "edi",
-    "r8d", "r9d", "r10d", "r11d", "r12d", "r13d", "r14d", "r15d"
-};
-
-static const char *register_names_16[] = {
-    "ax", "cx", "dx", "bx", "sp", "bp", "si", "di",
-    "r8w", "r9w", "r10w", "r11w", "r12w", "r13w", "r14w", "r15w"
-};
-
-static const char *register_names_8[] = {
-    "al", "cl", "dl", "bl", "spl", "bpl", "sil", "dil",
-    "r8b", "r9b", "r10b", "r11b", "r12b", "r13b", "r14b", "r15b"
-};
-
-static const char *register_names_xmm[] = {
-    "xmm0", "xmm1", "xmm2", "xmm3", "xmm4", "xmm5", "xmm6", "xmm7",
-    "xmm8", "xmm9", "xmm10", "xmm11", "xmm12", "xmm13", "xmm14", "xmm15"
-};
-
 typedef enum {
     JANET_SYSREG_8,
     JANET_SYSREG_16,
@@ -103,6 +78,9 @@ typedef struct {
     JanetSysIRLinkage *linkage;
     JanetSysIR *ir;
     JanetBuffer *buffer;
+    JanetBuffer *constant_data; /* A buffer of constants for RIP-relative addressing to point to */
+    uint32_t *v_rip_indicies; /* An array of pointers of all emitted addresses to patch at end. */
+    JanetTable *constant_to_data; /* Table mapping constants to index into v_constant_data (dedupe constants) */
     x64Reg *regs; /* Map IR virtual registers to hardware register or stack offset */
     JanetSysTypeLayout *layouts;
     JanetSysTypeLayout *ir_layouts;
@@ -317,6 +295,30 @@ static int operand_isreg(JanetSysx64Context *ctx, uint32_t o, uint32_t regindex)
     return reg.index == regindex;
 }
 
+/* Visit a constant and return the index into the constant data buffer. */
+static uint32_t janet_x64_constant(JanetSysx64Context *ctx, uint32_t const_index) {
+    Janet key = janet_wrap_number((double) const_index);
+    Janet check = janet_table_get(ctx->constant_to_data, key);
+    if (janet_checktype(check, JANET_NUMBER)) {
+        /* Constant has been seen before */
+        return (uint32_t) janet_unwrap_integer(check);
+    }
+    JanetSysConstant jsc = ctx->ir->constants[const_index];
+    JanetSysTypeInfo tinfo = ctx->linkage->type_defs[jsc.type];
+    /* TODO - check type and alignment for data types beyond pointers such as large struct and other immediates */
+    uint32_t index = ctx->constant_data->count;
+    switch (janet_type(jsc.value)) {
+        default:
+            janet_assert(0, "cannot emit constant");
+            break;
+        case JANET_STRING:
+            janet_assert(tinfo.prim == JANET_PRIM_POINTER, "expected pointer type for string constant");
+            janet_buffer_push_string(ctx->constant_data, janet_unwrap_string(jsc.value));
+            break;
+    }
+    return index;
+}
+
 /*
  * Machine code emission
  */
@@ -330,7 +332,7 @@ static const InstrChunk empty_chunk = { 0, 0 };
 
 static void i_chunk(JanetSysx64Context *C, InstrChunk c) {
     for (int i = 0; i < c.bytes; i++) {
-        janet_formatb(C->buffer, "0x%.2X,", c.data & 0xFF);
+        janet_buffer_push_u8(C->buffer, c.data & 0xFF);
         c.data = c.data >> 8;
     }
 }
@@ -347,22 +349,17 @@ static void i_combine(JanetSysx64Context *C,
     assert(mod_reg_rm.bytes < 3);
     assert(scaled_index.bytes < 2);
     assert(opcode < 512);
-    janet_buffer_push_cstring(C->buffer, "db ");
     i_chunk(C, prefix);
     if (opcode >= 256) {
-        janet_formatb(C->buffer, "0x%.2X,", 0x0Fu);
+        janet_buffer_push_u8(C->buffer, 0x0Fu);
         opcode -= 256;
     }
-    janet_formatb(C->buffer, "0x%.2X,", opcode);
+    janet_buffer_push_u8(C->buffer, opcode);
     i_chunk(C, mod_reg_rm);
     i_chunk(C, scaled_index);
     i_chunk(C, displacement);
     i_chunk(C, immediate);
-    if (msg) {
-        janet_formatb(C->buffer, "; %s\n", msg);
-    } else {
-        janet_buffer_push_cstring(C->buffer, "\n");
-    }
+    (void) msg;
 }
 
 typedef enum {
@@ -380,16 +377,19 @@ static void e_mov_ext(JanetSysx64Context *ctx, x64Reg d, x64Reg s, MoveMode mm,
 
     /* src is a constant */
     if (s.storage == JANET_SYSREG_CONSTANT) {
+        //uint32_t disp = janet_x64_constant(ctx, s.index);
         if (d.index >= 8) rex |= REX_R;
         if (d.kind >= JANET_SYSREG_64) rex |= REX_W;
         Janet c = ctx->ir->constants[s.index].value;
         int32_t imm = 0;
         uint64_t imm64 = 0;
         int is64 = 0;
+        //int isRipRel = 0;
         InstrChunk dispchunk = empty_chunk;
         if (janet_checktype(c, JANET_STRING)) {
             is64 = 1;
-            imm64 = (uint64_t) janet_unwrap_pointer(c);
+            imm64 = (uint64_t) janet_unwrap_pointer(c);// janet_x64_constant(ctx, s.index);
+            //isRipRel = 1;
         } else if (s.kind >= JANET_SYSREG_64) {
             is64 = 1;
             imm64 = janet_unwrap_u64(c);
@@ -407,7 +407,7 @@ static void e_mov_ext(JanetSysx64Context *ctx, x64Reg d, x64Reg s, MoveMode mm,
             }
             /* encode movabsq */
             rex |= REX_W;
-            imm64 = 0xDEADBEEFCAFEBABEULL;
+            // imm64 = 0xDEADBEEFCAFEBABEULL;
             opcode = 0xB8;
             opcode += (d.index & 7);
             if (d.index >= 8) rex |= REX_R;
@@ -496,7 +496,6 @@ static void e_mov_ext(JanetSysx64Context *ctx, x64Reg d, x64Reg s, MoveMode mm,
     if (!rex) prefix.bytes = 0;
     InstrChunk modregrm = {1, mod_rm};
     i_combine(ctx, prefix, opcode, modregrm, empty_chunk, dispchunk, empty_chunk, msg);
-    //janet_formatb(ctx->buffer, ";mov %s <- %s, mode=%d, %s\n", register_names[d.index], register_names[s.index], mm, sizestr);
 }
 
 static void e_mov(JanetSysx64Context *ctx, uint32_t dest, uint32_t src, const char *msg) {
@@ -516,9 +515,11 @@ static void e_fn_prefix(JanetSysx64Context *ctx, int32_t stack) {
         int b = (stack >> 8) & 0xFF;
         int c = (stack >> 16) & 0xFF;
         int d = (stack >> 24) & 0xFF;
-        janet_formatb(ctx->buffer, "db 0x55, 0x48, 0x89, 0xe5, 0x48, 0x81, 0xec, 0x%.2X, 0x%.2X, 0x%2X, 0x%2X ; function prefix\n", a, b, c, d);
+        uint8_t bytes[] = {0x55, 0x48, 0x89, 0xe5, 0x48, 0x81, 0xec, a, b, c, d};
+        janet_buffer_push_bytes(ctx->buffer, bytes, sizeof(bytes));
     } else {
-        janet_formatb(ctx->buffer, "db 0x55, 0x48, 0x89, 0xe5, 0x48, 0x83, 0xec, 0x%.2X ; function prefix\n", stack);
+        uint8_t bytes[] = {0x55, 0x48, 0x89, 0xe5, 0x48, 0x83, 0xec, stack};
+        janet_buffer_push_bytes(ctx->buffer, bytes, sizeof(bytes));
     }
 }
 
@@ -526,9 +527,11 @@ static void e_pushreg(JanetSysx64Context *ctx, uint32_t reg) {
     assert(reg < 16);
     if (reg >= 8) {
         /* Use REX prefix */
-        janet_formatb(ctx->buffer, "db 0x41, 0x%.2X ; push %s\n", 0x50 + (reg - 8), register_names[reg]);
+        uint8_t bytes[] = {0x41, 0x50 + (reg - 8)};
+        janet_buffer_push_bytes(ctx->buffer, bytes, sizeof(bytes));
     } else {
-        janet_formatb(ctx->buffer, "db 0x%.2X ; push %s\n", 0x50 + reg, register_names[reg]);
+        uint8_t bytes[] = {0x50 + reg};
+        janet_buffer_push_bytes(ctx->buffer, bytes, sizeof(bytes));
     }
 }
 
@@ -536,15 +539,18 @@ static void e_popreg(JanetSysx64Context *ctx, uint32_t reg) {
     assert(reg < 16);
     if (reg >= 8) {
         /* Use REX prefix */
-        janet_formatb(ctx->buffer, "db 0x41, 0x%.2X ; pop %s\n", 0x58 + (reg - 8), register_names[reg]);
+        uint8_t bytes[] = {0x41, 0x58 + (reg - 8)};
+        janet_buffer_push_bytes(ctx->buffer, bytes, sizeof(bytes));
     } else {
-        janet_formatb(ctx->buffer, "db 0x%.2X ; pop %s\n", 0x58 + reg, register_names[reg]);
+        uint8_t bytes[] = {0x58 + reg};
+        janet_buffer_push_bytes(ctx->buffer, bytes, sizeof(bytes));
     }
 }
 
 static void e_fn_suffix(JanetSysx64Context *ctx) {
     /* leave, ret */
-    janet_formatb(ctx->buffer, "db 0xc9, 0xc3 ; function suffix\n");
+    uint8_t bytes[] = {0xc9, 0xc3};
+    janet_buffer_push_bytes(ctx->buffer, bytes, sizeof(bytes));
 }
 
 /* Assembly emission */
@@ -557,47 +563,18 @@ static x64Reg mk_tmpreg(JanetSysx64Context *ctx, uint32_t src) {
     return tempreg;
 }
 
-static void sysemit_reg(JanetSysx64Context *ctx, x64Reg reg, const char *after) {
-    const char *sizestr = sysemit_sizestr_reg(reg);
-    if (reg.storage == JANET_SYSREG_STACK) {
-        // TODO - use LEA for parameters larger than a qword
-        janet_formatb(ctx->buffer, "%s [rbp-%u]", sizestr, reg.index);
-    } else if (reg.storage == JANET_SYSREG_STACK_PARAMETER) {
-        // TODO - use LEA for parameters larger than a qword
-        janet_formatb(ctx->buffer, "%s [rbp+%u]", sizestr, reg.index);
-    } else if (reg.kind == JANET_SYSREG_64) {
-        janet_formatb(ctx->buffer, "%s", register_names[reg.index]);
-    } else if (reg.kind == JANET_SYSREG_32) {
-        janet_formatb(ctx->buffer, "%s", register_names_32[reg.index]);
-    } else if (reg.kind == JANET_SYSREG_16) {
-        janet_formatb(ctx->buffer, "%s", register_names_16[reg.index]);
-    } else if (reg.kind == JANET_SYSREG_8) {
-        janet_formatb(ctx->buffer, "%s", register_names_8[reg.index]);
-    } else {
-        janet_formatb(ctx->buffer, "%s", register_names_xmm[reg.index]);
-    }
-    if (after) janet_buffer_push_cstring(ctx->buffer, after);
+static void sysemit_movreg(JanetSysx64Context *ctx, uint32_t regdest, uint32_t src) {
+    if (operand_isreg(ctx, src, regdest)) return;
+    x64Reg tempreg = mk_tmpreg(ctx, src);
+    tempreg.index = regdest;
+    e_mov_ext(ctx, tempreg, to_reg(ctx, src), MOV_FLAT, "sysemit_movreg");
 }
 
-static void sysemit_operand(JanetSysx64Context *ctx, uint32_t o, const char *after) {
-    if (o <= JANET_SYS_MAX_OPERAND) {
-        sysemit_reg(ctx, ctx->regs[o], NULL);
-    } else {
-        /* Constant */
-        uint32_t index = o - JANET_SYS_CONSTANT_PREFIX;
-        Janet c = ctx->ir->constants[index].value;
-        // TODO - do this properly
-        if (janet_checktype(c, JANET_STRING)) {
-            janet_formatb(ctx->buffer, "CONST_%d_%u", ctx->ir_index, index);
-        } else {
-            // TODO - do this properly too.
-            // Also figure out how to load large constants to a temporary register
-            // In x64, only move to register is allowed to take a 64 bit immediate, so
-            // our methodology here changes based on what kind of operand we need.
-            janet_formatb(ctx->buffer, "%V", c);
-        }
-    }
-    if (after) janet_buffer_push_cstring(ctx->buffer, after);
+static void sysemit_movfromreg(JanetSysx64Context *ctx, uint32_t dest, uint32_t srcreg) {
+    if (operand_isreg(ctx, dest, srcreg)) return;
+    x64Reg tempreg = mk_tmpreg(ctx, dest);
+    tempreg.index = srcreg;
+    e_mov_ext(ctx, ctx->regs[dest], tempreg, MOV_FLAT, "move from specific register");
 }
 
 /* A = A op B */
@@ -607,14 +584,16 @@ static void sysemit_binop(JanetSysx64Context *ctx, const char *op, uint32_t dest
         x64Reg tempreg = mk_tmpreg(ctx, dest);
         x64Reg srcreg = ctx->regs[src];
         e_mov_ext(ctx, tempreg, srcreg, MOV_FLAT, "mem -> RAX temp");
-        janet_formatb(ctx->buffer, "%s ", op);
-        sysemit_operand(ctx, dest, ", ");
-        sysemit_reg(ctx, tempreg, "\n");
-    } else {
-        janet_formatb(ctx->buffer, "%s ", op);
-        sysemit_operand(ctx, dest, ", ");
-        sysemit_operand(ctx, src, "\n");
-    }
+    } 
+    janet_formatb(ctx->buffer, "%s ", op);
+    //sysemit_operand(ctx, dest, ", ");
+    //sysemit_operand(ctx, src, "\n");
+}
+
+/* Dest = LHS op RHS */
+static void sysemit_threeop(JanetSysx64Context *ctx, const char *op, uint32_t dest, uint32_t lhs, uint32_t rhs) {
+    e_mov(ctx, dest, lhs, op);
+    sysemit_binop(ctx, op, dest, rhs);
 }
 
 /* dest = src[0] */
@@ -684,52 +663,15 @@ static void sysemit_store(JanetSysx64Context *ctx, uint32_t dest, uint32_t src)
     }
 }
 
-static void sysemit_movreg(JanetSysx64Context *ctx, uint32_t regdest, uint32_t src) {
-    if (operand_isreg(ctx, src, regdest)) return;
-    x64Reg tempreg = mk_tmpreg(ctx, src);
-    tempreg.index = regdest;
-    e_mov_ext(ctx, tempreg, to_reg(ctx, src), MOV_FLAT, "sysemit_movreg");
-}
-
-static void sysemit_movfromreg(JanetSysx64Context *ctx, uint32_t dest, uint32_t srcreg) {
-    if (operand_isreg(ctx, dest, srcreg)) return;
-    x64Reg tempreg = mk_tmpreg(ctx, dest);
-    tempreg.index = srcreg;
-    e_mov_ext(ctx, ctx->regs[dest], tempreg, MOV_FLAT, "move from specific register");
-}
-
 /* Move a value to a register, and save the contents of the old register on the stack */
 static void sysemit_mov_save(JanetSysx64Context *ctx, uint32_t regdest, uint32_t src) {
     e_pushreg(ctx, regdest);
     if (operand_isreg(ctx, src, regdest)) return;
     x64Reg tempreg = mk_tmpreg(ctx, src);
     tempreg.index = regdest;
-    janet_formatb(ctx->buffer, "; mov save %s <- %u\n", register_names[regdest], src);
     e_mov_ext(ctx, tempreg, to_reg(ctx, src), MOV_FLAT, "mov save");
 }
 
-static void sysemit_threeop(JanetSysx64Context *ctx, const char *op, uint32_t dest, uint32_t lhs, uint32_t rhs) {
-    e_mov(ctx, dest, lhs, op);
-    sysemit_binop(ctx, op, dest, rhs);
-}
-
-static void sysemit_threeop_nodeststack(JanetSysx64Context *ctx, const char *op, uint32_t dest, uint32_t lhs,
-                                        uint32_t rhs) {
-    if (operand_isstack(ctx, dest)) {
-        sysemit_movreg(ctx, RAX, lhs);
-        x64Reg tempreg;
-        tempreg.kind = get_slot_regkind(ctx, dest);
-        tempreg.storage = JANET_SYSREG_REGISTER;
-        tempreg.index = RAX;
-        janet_formatb(ctx->buffer, "%s ", op);
-        sysemit_reg(ctx, tempreg, ", ");
-        sysemit_operand(ctx, lhs, "\n");
-        sysemit_movfromreg(ctx, dest, RAX);
-    } else {
-        sysemit_threeop(ctx, op, dest, lhs, rhs);
-    }
-}
-
 static void sysemit_three_inst(JanetSysx64Context *ctx, const char *op, JanetSysInstruction instruction) {
     sysemit_threeop(ctx, op, instruction.three.dest, instruction.three.lhs, instruction.three.rhs);
 }
@@ -778,7 +720,7 @@ static int sysemit_comp(JanetSysx64Context *ctx, uint32_t index,
             /* Zero the upper bits */
             sysemit_binop(ctx, "xor", instruction.three.dest, instruction.three.dest);
         }
-        janet_formatb(ctx->buffer, "%s %s\n", set, register_names_8[instruction.three.dest]);
+        //janet_formatb(ctx->buffer, "%s %s\n", set, register_names_8[instruction.three.dest]);
         return 0;
     }
 }
@@ -846,7 +788,7 @@ static void sysemit_sysv_call(JanetSysx64Context *ctx, JanetSysInstruction instr
     for (int32_t argo = argcount - 1; argo >= 6; argo--) {
         janet_panic("nyi push sysv args");
         janet_formatb(buffer, "push ");
-        sysemit_operand(ctx, args[argo], "\n");
+        //sysemit_operand(ctx, args[argo], "\n");
     }
     if (instruction.opcode == JANET_SYSOP_SYSCALL) {
         sysemit_movreg(ctx, RAX, instruction.call.callee);
@@ -855,7 +797,7 @@ static void sysemit_sysv_call(JanetSysx64Context *ctx, JanetSysInstruction instr
         /* Save RAX to number of floating point args for varags - for now, always 0 :) */
         janet_formatb(buffer, "db 0x48, 0x31, 0xc0 ; xor rax, rax\n");
         janet_formatb(buffer, "call ");
-        sysemit_operand(ctx, instruction.call.callee, "\n");
+        //sysemit_operand(ctx, instruction.call.callee, "\n");
     }
     if (save_r11) e_popreg(ctx, 11);
     if (save_r10) e_popreg(ctx, 10);
@@ -895,7 +837,7 @@ static void sysemit_win64_call(JanetSysx64Context *ctx, JanetSysInstruction inst
         janet_formatb(buffer, "syscall\n");
     } else {
         janet_formatb(buffer, "call ");
-        sysemit_operand(ctx, instruction.call.callee, "\n");
+        //sysemit_operand(ctx, instruction.call.callee, "\n");
     }
     if (argcount > 4) {
         janet_formatb(buffer, "add rsp, %u\n", 8 * (argcount - 4));
@@ -909,12 +851,42 @@ static void sysemit_win64_call(JanetSysx64Context *ctx, JanetSysInstruction inst
     if (instruction.call.flags & JANET_SYS_CALLFLAG_HAS_DEST) sysemit_movfromreg(ctx, instruction.call.dest, RAX);
 }
 
+static void emit_nasm_string(JanetBuffer *buffer, const uint8_t *str, int32_t len) {
+    /* Nasm syntax */
+    int in_string = 0;
+    for (int32_t ci = 0; ci < len; ci++) {
+        int c = str[ci];
+        if (c < 32) {
+            if (in_string) {
+                janet_formatb(buffer, "\", %d", c);
+            } else {
+                janet_formatb(buffer, ci ? ", %d" : "%d", c);
+            }
+            in_string = 0;
+        } else {
+            if (!in_string) {
+                janet_buffer_push_cstring(buffer, ci ? ", \"" : "\"");
+            }
+            janet_buffer_push_u8(buffer, c);
+            in_string = 1;
+        }
+    }
+    if (!in_string) {
+        janet_buffer_push_cstring(buffer, ", 0\n");
+    } else {
+        janet_buffer_push_cstring(buffer, "\", 0\n");
+    }
+}
+
 void janet_sys_ir_lower_to_x64(JanetSysIRLinkage *linkage, JanetSysTarget target, JanetBuffer *buffer) {
 
     /* Partially setup context */
     JanetSysx64Context ctx;
     ctx.linkage = linkage;
     ctx.buffer = buffer;
+    ctx.constant_data = janet_buffer(0);
+    ctx.v_rip_indicies = NULL;
+    ctx.constant_to_data = janet_table(0);
     ctx.layouts = janet_smalloc(linkage->type_def_count * sizeof(JanetSysTypeLayout));
     for (uint32_t i = 0; i < linkage->type_def_count; i++) {
         ctx.layouts[i] = get_x64layout(linkage->type_defs[i]);
@@ -1018,7 +990,7 @@ void janet_sys_ir_lower_to_x64(JanetSysIRLinkage *linkage, JanetSysTarget target
                     sysemit_three_inst(&ctx, "sub", instruction);
                     break;
                 case JANET_SYSOP_MULTIPLY:
-                    sysemit_threeop_nodeststack(&ctx, "imul", instruction.three.dest,
+                    sysemit_threeop(&ctx, "imul", instruction.three.dest,
                                                 instruction.three.lhs, instruction.three.rhs);
                     break;
                 case JANET_SYSOP_DIVIDE:
@@ -1073,7 +1045,7 @@ void janet_sys_ir_lower_to_x64(JanetSysIRLinkage *linkage, JanetSysTarget target
                 case JANET_SYSOP_BRANCH_NOT:
                     janet_formatb(buffer, "test ");
                     // TODO - ensure branch condition is not a const
-                    sysemit_operand(&ctx, instruction.branch.cond, ", 0\n");
+                    //sysemit_operand(&ctx, instruction.branch.cond, ", 0\n");
                     janet_formatb(buffer,
                                   "%s label_%d_%u\n",
                                   instruction.opcode == JANET_SYSOP_BRANCH ? "jnz" : "jz",
@@ -1103,39 +1075,20 @@ void janet_sys_ir_lower_to_x64(JanetSysIRLinkage *linkage, JanetSysTarget target
     }
     /* End section .text */
 
+    /* rodata */
     janet_formatb(buffer, "\nsection .rodata\n");
+    janet_formatb(buffer, "CONST_DATA: db ");
+    emit_nasm_string(buffer, ctx.constant_data->data, ctx.constant_data->count);
 
+    /* old rodata */
     for (int32_t i = 0; i < linkage->ir_ordered->count; i++) {
         JanetSysIR *ir = janet_unwrap_pointer(linkage->ir_ordered->data[i]);
         /* Emit constant strings */
         for (uint32_t j = 0; j < ir->constant_count; j++) {
             if (janet_checktype(ir->constants[j].value, JANET_STRING)) {
+                janet_formatb(buffer, "CONST_%d_%d: db ", i, j);
                 JanetString str = janet_unwrap_string(ir->constants[j].value);
-                janet_formatb(buffer, "CONST_%d_%u: db ", i, j);
-                /* Nasm syntax */
-                int in_string = 0;
-                for (int32_t ci = 0; ci < janet_string_length(str); ci++) {
-                    int c = str[ci];
-                    if (c < 32) {
-                        if (in_string) {
-                            janet_formatb(buffer, "\", %d", c);
-                        } else {
-                            janet_formatb(buffer, ci ? ", %d" : "%d", c);
-                        }
-                        in_string = 0;
-                    } else {
-                        if (!in_string) {
-                            janet_buffer_push_cstring(buffer, ci ? ", \"" : "\"");
-                        }
-                        janet_buffer_push_u8(buffer, c);
-                        in_string = 1;
-                    }
-                }
-                if (!in_string) {
-                    janet_buffer_push_cstring(buffer, ", 0\n");
-                } else {
-                    janet_buffer_push_cstring(buffer, "\", 0\n");
-                }
+                emit_nasm_string(buffer, str, janet_string_length(str));
             }
         }
     }
diff --git a/test/helper.janet b/test/helper.janet
index 4a6c8596..511d8f12 100644
--- a/test/helper.janet
+++ b/test/helper.janet
@@ -27,7 +27,7 @@
   (if x
     (when is-verbose (eprintf "\e[32m✔\e[0m %s: %s: %v" line-info (describe e) x))
     (do
-      (eprintf "\e[31m✘\e[0m %s: %s: %v" line-info (describe e) x) (eflush)))
+      (eprintf "\e[31m✘\e[0m %s: %s: %v" line-info (string e) x) (eflush)))
   x)
 
 (defn skip-asserts
diff --git a/test/suite-sysir.janet b/test/suite-sysir.janet
index 1cb2bd77..06f743a9 100644
--- a/test/suite-sysir.janet
+++ b/test/suite-sysir.janet
@@ -24,4 +24,27 @@
 (use ../examples/sysir/frontend)
 (assert true) # smoke test
 
+(def janet (dyn *executable*))
+(def run (filter next (string/split " " (os/getenv "SUBRUN" ""))))
+
+(defn do-expect-directory
+  "Iterate a directory, evaluating all scripts in the directory. Assert that the captured output of the script
+  is as expected according to a matching .expect file."
+  [dir]
+  (each path (sorted (os/dir dir))
+    (when (string/has-suffix? ".janet" path)
+      (def fullpath (string dir "/" path))
+      (def proc (os/spawn [;run janet fullpath] :p {:out :pipe :err :out}))
+      (def buff @"")
+      (var ret-code nil)
+      (ev/gather
+        (while (ev/read (proc :out) 4096 buff))
+        (set ret-code (os/proc-wait proc)))
+      (def expect-file (string dir "/" path ".expect"))
+      (def expected-out (slurp expect-file))
+      (assert (= (string/trim expected-out) (string/trim buff))
+              (string "\nfile: " fullpath "\nexpected:\n======\n" expected-out "\n======\ngot:\n======\n" buff "\n======\n")))))
+
+(do-expect-directory "test/sysir")
+
 (end-suite)
diff --git a/examples/sysir/arrays1.janet b/test/sysir/arrays1.janet
similarity index 93%
rename from examples/sysir/arrays1.janet
rename to test/sysir/arrays1.janet
index b51eafd6..4f9642ef 100644
--- a/examples/sysir/arrays1.janet
+++ b/test/sysir/arrays1.janet
@@ -25,4 +25,4 @@
 (sysir/asm ctx types-asm)
 (sysir/asm ctx add-asm)
 (sysir/asm ctx sub-asm)
-(print (sysir/to-c ctx))
+(printf "%.99j" (sysir/to-ir ctx))
diff --git a/test/sysir/arrays1.janet.expect b/test/sysir/arrays1.janet.expect
new file mode 100644
index 00000000..134285e7
--- /dev/null
+++ b/test/sysir/arrays1.janet.expect
@@ -0,0 +1 @@
+@[@[(type-prim Double f64) (type-array BigVec Double 100)] @[(parameter-count 0)] @[(link-name "add_vector") (parameter-count 2) (type-bind 0 BigVec) (type-bind 1 BigVec) (type-bind 2 BigVec) (add 2 0 1) (return 2)] @[(link-name "sub_vector") (parameter-count 2) (type-bind 0 BigVec) (type-bind 1 BigVec) (type-bind 2 BigVec) (subtract 2 0 1) (return 2)]]
diff --git a/examples/sysir/arrays2.janet b/test/sysir/arrays2.janet
similarity index 74%
rename from examples/sysir/arrays2.janet
rename to test/sysir/arrays2.janet
index 41f089e4..6aafe8dd 100644
--- a/examples/sysir/arrays2.janet
+++ b/test/sysir/arrays2.janet
@@ -16,8 +16,7 @@
 
 (def ctx (sysir/context))
 (sysir/asm ctx ir-asm)
-(print (sysir/to-c ctx))
-(printf "%.99M" (sysir/to-ir ctx))
-(print (sysir/scalarize ctx))
-(printf "%.99M" (sysir/to-ir ctx))
+(printf "%j" (sysir/to-ir ctx))
+(sysir/scalarize ctx)
+(printf "%j" (sysir/to-ir ctx))
 (print (sysir/to-c ctx))
diff --git a/test/sysir/arrays2.janet.expect b/test/sysir/arrays2.janet.expect
new file mode 100644
index 00000000..1064d99b
--- /dev/null
+++ b/test/sysir/arrays2.janet.expect
@@ -0,0 +1,66 @@
+@[@[(type-prim Double f64) (type-array BigVec Double 100) (type-pointer BigVecP BigVec)] @[(link-name "add_vectorp") (parameter-count 2) (type-bind 0 BigVecP) (type-bind 1 BigVecP) (type-bind 2 BigVecP) (add 2 0 1) (return 2)]]
+@[@[(type-prim Double f64) (type-array BigVec Double 100) (type-pointer BigVecP BigVec)] @[(link-name "add_vectorp") (parameter-count 2) (type-bind 0 BigVecP) (type-bind 1 BigVecP) (type-bind 2 BigVecP) (type-bind 3 U32Index) (type-bind 5 PointerTo) (type-bind 6 PointerTo) (type-bind 7 PointerTo) (type-bind 4 Boolean) (load 3 [U32Index 0]) (label 7) (gte 4 3 [U32Index 0]) (branch 4 21) (apgetp 5 0 3) (apgetp 6 1 3) (apgetp 7 2 3) (add 7 5 6) (add 3 3 [U32Index 1]) (jump 7) (label 21) (return 2)]]
+#include <stddef.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <sys/syscall.h>
+#define _t0 void
+
+#line 6
+typedef double _t1;
+#line 7
+typedef struct { _t1 els[100]; } _t2;
+#line 8
+typedef _t2 *_t3;
+
+
+_t3 add_vectorp(_t3 _r0, _t3 _r1)
+{
+    _t3 _r2;
+    _t4 _r3;
+    _t5 _r4;
+    _t6 _r5;
+    _t6 _r6;
+    _t6 _r7;
+
+#line 6
+#line 7
+#line 8
+#line 11
+#line 12
+#line 13
+#line 14
+#line 14
+#line 14
+#line 14
+#line 14
+#line 14
+  _r3 = *(0);
+#line 14
+
+_label_0:
+#line 14
+  _r4 = _r3 > 0;
+#line 14
+  if (_r4) goto _label_1;
+#line 14
+  _r5 = &(_r0->els[_r3]);
+#line 14
+  _r6 = &(_r1->els[_r3]);
+#line 14
+  _r7 = &(_r2->els[_r3]);
+#line 14
+  _r7 = _r5 + _r6;
+#line 14
+  _r3 = _r3 + 1;
+#line 14
+  goto _label_0;
+#line 14
+
+_label_1:
+#line 15
+  return _r2;
+}
diff --git a/examples/sysir/basic1.janet b/test/sysir/basic1.janet
similarity index 74%
rename from examples/sysir/basic1.janet
rename to test/sysir/basic1.janet
index 73193a80..b9b6eef2 100644
--- a/examples/sysir/basic1.janet
+++ b/test/sysir/basic1.janet
@@ -5,7 +5,7 @@
     (type-prim Int s32)
     (type-prim Double f64)
     (type-struct MyPair 0 1)
-    (type-pointer PInt 0)
+    (type-pointer PInt Int)
     (type-array DoubleArray 1 1024)
 
     # Declarations
@@ -18,14 +18,14 @@
     (bind 6 MyPair)
 
     # Code
-    (constant 0 10)
-    (constant 0 21)
+    (move 0 (Int 10))
+    (move 0 (Int 21))
     :location
     (add 2 1 0)
-    (constant 3 1.77)
-    (call 3 sin 3)
+    (move 3 (Double 1.77))
+    (call :default 3 (PInt sin) 3)
     (cast bob 2)
-    (call :default bob test_function)
+    (call :default bob (PInt test_function))
     (add 5 bob 3)
     (jump :location)
     (return 5)))
diff --git a/test/sysir/basic1.janet.expect b/test/sysir/basic1.janet.expect
new file mode 100644
index 00000000..e875ee50
--- /dev/null
+++ b/test/sysir/basic1.janet.expect
@@ -0,0 +1,71 @@
+#include <stddef.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <sys/syscall.h>
+#define _t0 void
+
+#line 5
+typedef int32_t _t1;
+#line 6
+typedef double _t2;
+#line 7
+typedef struct {
+    _t0 _f0;
+    _t1 _f1;
+} _t3;
+#line 8
+typedef _t1 *_t4;
+#line 9
+typedef struct { _t1 els[1024]; } _t5;
+
+
+_t2 test_function()
+{
+    _t1 _r0;
+    _t1 _r1;
+    _t1 _r2;
+    _t2 _r3;
+    _t2 _r4;
+    _t2 _r5;
+    _t3 _r6;
+
+#line 5
+#line 6
+#line 7
+#line 7
+#line 8
+#line 9
+#line 12
+#line 13
+#line 14
+#line 15
+#line 16
+#line 17
+#line 18
+#line 21
+  _r0 = 10;
+#line 22
+  _r0 = 21;
+
+_label_0:
+#line 24
+  _r2 = _r1 + _r0;
+#line 25
+  _r3 = 1.77;
+#line 26
+  _r3 = sin(_r3);
+#line 26
+#line 27
+  _r4 = (_t2) _r2;
+#line 28
+  _r4 = test_function();
+#line 29
+  _r5 = _r4 + _r3;
+#line 30
+  goto _label_0;
+#line 31
+  return _r5;
+}
diff --git a/examples/sysir/basic2.janet b/test/sysir/basic2.janet
similarity index 100%
rename from examples/sysir/basic2.janet
rename to test/sysir/basic2.janet
diff --git a/test/sysir/basic2.janet.expect b/test/sysir/basic2.janet.expect
new file mode 100644
index 00000000..1634764a
--- /dev/null
+++ b/test/sysir/basic2.janet.expect
@@ -0,0 +1 @@
+nope
diff --git a/test/sysir/smoke.janet b/test/sysir/smoke.janet
new file mode 100644
index 00000000..2ed187c3
--- /dev/null
+++ b/test/sysir/smoke.janet
@@ -0,0 +1 @@
+(print "hello")
diff --git a/test/sysir/smoke.janet.expect b/test/sysir/smoke.janet.expect
new file mode 100644
index 00000000..ce013625
--- /dev/null
+++ b/test/sysir/smoke.janet.expect
@@ -0,0 +1 @@
+hello