got a working floor! (bouncy though)

code/duffle/gte.h

@@ -647,3 +647,6 @@ enum {
 		asm_clobber: clb_system, rlit(R_T4_Code), rlit(R_T5_Code), rlit(R_T6_Code) \
 	)
 
+// TODO(Ed): Resolve magic number.
+/* PsyQ Compliant AVSZ3 Command Word */
+#define gte_cmdw_avsz3 (gte_cmd_base | 0x0158002D)

code/duffle/lottes_tape.h

@@ -31,12 +31,14 @@ FI_ void tape_run(Slice_U4 tape, B1** r_prim_cursor, void* face_cursor, void* ve
     register void* r_t6 rgcc(R_T6) = ot_base;
 
     asm volatile(
-        "move  $11, $31;"     /* Manually save $ra to $t3 to protect against GCC bugs */
+        "addiu $sp, $sp, -8;" /* Allocate stack space */
+        "sw    $31, 0($sp);"  /* Safely backup $ra to the stack */
         "lw    $25, 0(%0);"   
         "addiu %0, %0, 4;"    
         "jalr  $25;"          
         "nop;"                
-        "move  $31, $11;"     /* Restore $ra */
+        "lw    $31, 0($sp);"  /* Restore $ra from stack */
+        "addiu $sp, $sp, 8;"  /* Deallocate stack space */
         : "+r"(tp), "+r"(pcur), "+r"(r_t4), "+r"(r_t5), "+r"(r_t6)
         : 
         : "at", "v0", "v1", "t0", "t1", "t2", "t3", "t9", "memory" 
@@ -97,16 +99,17 @@ internal Code CodeBlob_(atom_floor_tri) {
     nop, nop, /* Wait for NCLIP to finish */
 
     /* 4. Check NCLIP. 
-       If MAC0 <= 0 (Backface), branch to end.
+       Temporarily disabled backface culling to ensure floor is visible regardless of winding!
-       Target is 28 instructions past the delay slot. */
+       To re-enable: replace the two nops below with `branch_le_zero(R_T0, 30)` */
     gte_mf(R_T0, C2_MAC0),
-    branch_le_zero(R_T0, 28), 
+    nop,                      /* <--- FILL LOAD DELAY SLOT */
+    nop,                      /* branch_le_zero(R_T0, 30), <-- CULLING DISABLED */
     nop,                      /* <--- DELAY SLOT (Index 0) */
 
     /* 5. Store Primitive Data */
     /*  1 */ store_word(R_0, R_T7,  0), 
-    /*  2 */ load_ui(R_AT, 0x20FF),     /* High: Code 0x20 + Color R:FF */
+    /*  2 */ load_ui(   R_AT,       0x20FF),  /* High: Code 0x20 + Color B:FF */
-    /*  3 */ or_i(R_AT, R_AT, 0xFFFF),  /* Low: Color G:FF, B:FF */
+    /*  3 */ or_i(      R_AT, R_AT, 0xFFFF),  /* Low: Color G:FF, R:FF (White) */
     /*  4 */ store_word(R_AT, R_T7, 4),
     /*  5 */ enc_gte_sw(C2_SXY0, R_T7, 8),
     /*  6 */ enc_gte_sw(C2_SXY1, R_T7, 12),
@@ -115,33 +118,41 @@ internal Code CodeBlob_(atom_floor_tri) {
     /* 6. OT Insertion with Bounds Checking */
     /*  8 */ nop, 
     /*  9 */ nop, 
-    /* 10 */ enc_gte_cmd(0x2D),         /* AVSZ3 */
+    /* 10 */ gte_cmdw_avsz3,            
     /* 11 */ nop,                       /* Wait for AVSZ3 */
     /* 12 */ nop,                       /* Wait for AVSZ3 */
     /* 13 */ gte_mf(R_T1, C2_OTZ),      /* T1 = Depth index */
     
     /* Bounds Check: OTZ < 2048 */
-    /* 14 */ add_ui(R_AT, R_0, 2048),   /* <--- FIXED: Use add_ui for small constants! */
+    /* 14 */ add_ui(      R_AT, R_0,  2048),   
     /* 15 */ slt_u(       R_AT, R_T1, R_AT), /* AT = (OTZ < 2048) ? 1 : 0 */
-    /* 16 */ branch_equal(R_AT, R_0, 11), /* If AT == 0, skip to end (11 instrs past delay) */
+    /* 16 */ branch_equal(R_AT, R_0,  13),   /* If AT == 0, skip to end (13 instrs past delay) */
     /* 17 */ nop, /* <--- DELAY SLOT (Index 0 for Bounds branch) */
     
+    /* CORRECTED DMA TAG LOGIC */
     /*  18 (1)  */ shift_ll(  R_T1, R_T1, 2), 
     /*  19 (2)  */ add_u(     R_T1, R_T1, R_T6),    /* T1 = &OrderingTable[OTZ] */
-    /*  20 (3)  */ load_word(R_AT, R_T1, 0),        /* AT = current head */
-    /*  21 (4)  */ store_word(R_AT, R_T7, 0),       /* prim->next = head */
     
-    /* Create Tag in AT: Len 4 (0x04) in top 8 bits, T7 in bottom 24 */
+    /*  20 (3)  */ load_word( R_AT, R_T1, 0),       /* AT = current head (old_ot) */
-    /*  22 (5)  */ shift_ll(R_AT, R_T7, 8),
+    /*  21 (4)  */ load_ui(   R_V0, 0x0400),        /* V0 = 0x04000000 (Length = 4) */
-    /*  23 (6)  */ shift_lr(R_AT, R_AT, 8),         /* AT = T7 & 0x00FFFFFF */
-    /*  24 (7)  */ load_ui(R_V0, 0x0400),           /* V0 = 0x04000000 (Here LUI is correct!) */
-    /*  25 (8)  */ or_u(R_AT, R_AT, R_V0),          /* AT = Tag */
     
-    /*  26 (9)  */ store_word(R_AT, R_T1, 0),       /* OrderingTable[OTZ] = Tag */
+    /* Strip upper 8 bits from old_ot */
-    /*  27 (10) */ add_ui(R_T7, R_T7, 20),          /* Advance Prim Cursor (5 words) */
+    /*  22 (5)  */ shift_ll(R_AT, R_AT, 8),
+    /*  23 (6)  */ shift_lr(R_AT, R_AT, 8),         /* AT &= 0x00FFFFFF */
+    
+    /* Merge length into prim->tag */
+    /*  24 (7)  */ or_u(R_AT, R_AT, R_V0),          /* AT |= 0x04000000 */
+    /*  25 (8)  */ store_word(R_AT, R_T7, 0),       /* prim->tag = AT */
+    
+    /* Create OT Tag: Len 0 (0x00) in top 8 bits, T7 in bottom 24 */
+    /*  26 (9)  */ shift_ll(R_AT, R_T7, 8),
+    /*  27 (10) */ shift_lr(R_AT, R_AT, 8),         /* AT = T7 & 0x00FFFFFF */
+    /*  28 (11) */ store_word(R_AT, R_T1, 0),       /* OrderingTable[OTZ] = AT */
+    
+    /*  29 (12) */ add_ui(    R_T7, R_T7, 20),      /* Advance Prim Cursor (5 words) */
 
     /* 7. Yield */
-    /*  28 (11) */ add_ui(R_T4, R_T4, 8),           /* Advance Face Cursor (4 * S2 = 8 bytes) */
+    /*  30 (13) */ add_ui(R_T4, R_T4, 8),           /* Advance Face Cursor (4 * S2 = 8 bytes) */
     mips_yield
 };
 
@@ -153,8 +164,8 @@ internal Code CodeBlob_(atom_diag_yield) {
 /* DIAGNOSTIC 2: Pure memory test (No GTE). Draws a fixed cyan triangle. */
 internal Code CodeBlob_(atom_diag_color) {
     store_word(R_0, R_T7, 0), 
-    load_ui(R_AT, 0x2000),     
+    load_ui(R_AT, 0x20FF),      /* High: Code 0x20 + Color B:FF */
-    or_i(R_AT, R_AT, 0xFFFF),  
+    or_i(R_AT, R_AT, 0xFF00),   /* Low:  Color G:FF, R:00 (Cyan) */
     store_word(R_AT, R_T7, 4),
     
     /* Fake coordinates - Swapped winding order to prevent GPU culling! */
@@ -167,7 +178,7 @@ internal Code CodeBlob_(atom_diag_color) {
     add_u(R_T1, R_T1, R_T6),         
     
     load_word(R_AT, R_T1, 0),        
-    load_ui(R_V0, 0x0400),
+    load_ui(R_V0, 0x0400),           /* <--- Fills load delay slot! */
     store_word(R_AT, R_T7, 0),       
     
     shift_ll(R_AT, R_T7, 8), shift_lr(R_AT, R_AT, 8),         

code/gte_hello/hello_gte.c

@@ -286,11 +286,10 @@ void update(PrimitiveArena* pa, U4* ordering_buf)
 		static_mem.floor.rot.y += 5;
 	}
 	// Draw floor tape method
-	if (0)
+	if (1)
 	{
     LP_ U4 mem_temp_tape[512]; // Buffer for function addresses
-    FArena tape_arena; 
+    FArena tape_arena; farena_init(&tape_arena, slice_ut(mem_temp_tape, S_(mem_temp_tape)));
-    farena_init(&tape_arena, slice_ut(mem_temp_tape, S_(mem_temp_tape)));
     
     TapeBuilder tb = tb_begin(&tape_arena); {
         // Setup state atoms
@@ -315,7 +314,7 @@ void update(PrimitiveArena* pa, U4* ordering_buf)
     static_mem.floor.rot.y += 5;
 	}
 	// --- TAPE DIAGNOSTICS ---
-	if (1)
+	if (0)
 	{
 		LP_ U4 mem_temp_tape[512]; 
 		FArena tape_arena;