#ifdef INTELLISENSE_DIRECTIVES # pragma once # include "dsl.h" # include "math.h" # include "mips.h" #endif /* ============================================================================ * gte.h — Geometry Transformation Engine (COP2) for the PS1 * ============================================================================ * * Hand-rolled DSL for emitting GTE/MIPS instruction words as raw `.word` * constants from C. No GCC inline-assembly string syntax in the code body. * * PHILOSOPHY * ---------- * 1. A 32-bit instruction word is composed from per-field encoders. Each * encoder knows only its own bit range; the composite ORs them together. * No magic numbers inside any encoder body — every shift and mask is a * named constant from the bitfield-layout enum below. * * 2. Pure (compile-time) instructions — every GTE *command* (RTPS, RTPT, * NCLIP, MVMVA, …) and every COP2 *transfer* (ctc2/cfc2) with a constant * rs/rt/rd — are emitted as a single integer constant via * `asm_inline(...)` from gcc_asm.h. The C compiler constant-folds * these into `.word` directives in .rodata. * * 3. Runtime-base-register instructions (lwc2, swc2, lw, sw, …) cannot be * a pure compile-time word because the `rs` field is chosen by the * compiler at codegen. For these we use a "placeholder-pun" pattern: * a fixed register number (R_T4 = $12) is baked into the rs field of * the `.word` constant, and the macro declares a `"r"(arg)` input * constraint plus a clobber on the same register. The compiler is * therefore *forced* to bind `arg` to that exact register, and the * constant is correct. * * USAGE * ----- * // Pure command sequence — all bits compile-time: * asm volatile( * asm_inline( gte_cmd_rtpt , gte_cmd_nclip , gte_cmd_avsz3 ) * asm_clobber( clb_system ) * ); * * // Runtime-base-register load — caller picks the base GPR: * register V3_S2* p_in_12 __asm__("$12") = verts[0].ptr; * gte_load_v0(p_in_12, R_T4); // R_T4 = 12 = $t4 = $12 * * // Three independent bases for an RTPT pipeline: * register V3_S2* p0 __asm__("$12") = verts[0].ptr; * register V3_S2* p1 __asm__("$13") = verts[1].ptr; * register V3_S2* p2 __asm__("$14") = verts[2].ptr; * gte_load_v0(p0, R_T4); * gte_load_v1(p1, R_T5); * gte_load_v2(p2, R_T6); * gte_rtpt(); * * STYLE NOTES * ----------- * - Per-field encoders are named `enc_gte_(value)` and each one * self-masks its argument before shifting. Mirrors the `enc_op / enc_rs * / enc_rt / ...` family in mips.h. * - The composite `enc_gte_cmdw(sf, mx, v, cv, lm, cmd)` is a flat OR of * the per-field encoders, plus the COP2/CO base. * - Pre-baked shortcuts (`gte_cmd_rtpt`, `gte_cmd_rtps`, …) are defined * for the common cases so call sites read like assembly source. * - All register/field values are enums (not `#define`s) so they show up * in debugger symbol tables and IDE autocomplete. * * SEE ALSO * -------- * - gcc_asm.h: the `.word` emitter (`asm_inline`, `asm_clobber`, clobbers) * - mips.h: the MIPS encoder layer this builds on */ /* C2 data registers */ /* --- GTE Data Registers (Coprocessor 2) --- * Preprocessor-visible integer ids for the COP2 data register file. * Each enum value is bound to a parallel `_Code` `#define` so the * preprocessor can stringify the integer (for `reg_str`/`rgcc` paths). * Same pattern as the GPR `_Code` set in mips.h. */ #define C2_VXY0_Code 0 #define C2_VZ0_Code 1 #define C2_VXY1_Code 2 #define C2_VZ1_Code 3 #define C2_VXY2_Code 4 #define C2_VZ2_Code 5 #define C2_RGB_Code 6 #define C2_OTZ_Code 7 #define C2_IR0_Code 8 #define C2_IR1_Code 9 #define C2_IR2_Code 10 #define C2_IR3_Code 11 #define C2_SXY0_Code 12 #define C2_SXY1_Code 13 #define C2_SXY2_Code 14 #define C2_SXYP_Code 15 #define C2_SZ0_Code 16 #define C2_SZ1_Code 17 #define C2_SZ2_Code 18 #define C2_SZ3_Code 19 #define C2_RGB0_Code 20 #define C2_RGB1_Code 21 #define C2_RGB2_Code 22 #define C2_RES1_Code 23 #define C2_MAC0_Code 24 #define C2_MAC1_Code 25 #define C2_MAC2_Code 26 #define C2_MAC3_Code 27 #define C2_IRGB_Code 28 #define C2_ORGB_Code 29 #define C2_LZCS_Code 30 #define C2_LZCR_Code 31 enum { C2_VXY0 = C2_VXY0_Code, C2_VZ0 = C2_VZ0_Code, C2_VXY1 = C2_VXY1_Code, C2_VZ1 = C2_VZ1_Code, C2_VXY2 = C2_VXY2_Code, C2_VZ2 = C2_VZ2_Code, C2_RGB = C2_RGB_Code, C2_OTZ = C2_OTZ_Code, C2_IR0 = C2_IR0_Code, C2_IR1 = C2_IR1_Code, C2_IR2 = C2_IR2_Code, C2_IR3 = C2_IR3_Code, C2_SXY0 = C2_SXY0_Code, C2_SXY1 = C2_SXY1_Code, C2_SXY2 = C2_SXY2_Code, C2_SXYP = C2_SXYP_Code, C2_SZ0 = C2_SZ0_Code, C2_SZ1 = C2_SZ1_Code, C2_SZ2 = C2_SZ2_Code, C2_SZ3 = C2_SZ3_Code, C2_RGB0 = C2_RGB0_Code, C2_RGB1 = C2_RGB1_Code, C2_RGB2 = C2_RGB2_Code, C2_RES1 = C2_RES1_Code, C2_MAC0 = C2_MAC0_Code, C2_MAC1 = C2_MAC1_Code, C2_MAC2 = C2_MAC2_Code, C2_MAC3 = C2_MAC3_Code, C2_IRGB = C2_IRGB_Code, C2_ORGB = C2_ORGB_Code, C2_LZCS = C2_LZCS_Code, C2_LZCR = C2_LZCR_Code }; /* Semantic Aliases for GTE Data Registers */ enum { gte_in_v0_xy = C2_VXY0, /* Input Vector 0 (X, Y) */ gte_in_v0_z = C2_VZ0, /* Input Vector 0 (Z) */ gte_in_v1_xy = C2_VXY1, /* Input Vector 1 (X, Y) */ gte_in_v1_z = C2_VZ1, /* Input Vector 1 (Z) */ gte_in_v2_xy = C2_VXY2, /* Input Vector 2 (X, Y) */ gte_in_v2_z = C2_VZ2, /* Input Vector 2 (Z) */ gte_in_rgb = C2_RGB, /* Input Color (R, G, B, Code) */ gte_out_scr_xy0 = C2_SXY0, /* Output Screen Coord 0 (X, Y) */ gte_out_scr_xy1 = C2_SXY1, /* Output Screen Coord 1 (X, Y) */ gte_out_scr_xy2 = C2_SXY2, /* Output Screen Coord 2 (X, Y) */ gte_out_depth = C2_OTZ, /* Output Ordering Table Z (Depth) */ gte_math_accum0 = C2_MAC0, /* Math Accumulator 0 */ gte_math_accum1 = C2_MAC1, /* Math Accumulator 1 */ gte_math_accum2 = C2_MAC2, /* Math Accumulator 2 */ }; /* --- GTE Command Semantics (The Bitfield Meanings) --- * A GTE command is a single 32-bit word sent to COP2. * It is highly configurable via bitfields. */ enum { /* Shift Fraction (Bit 19) - Determines fixed-point division */ gte_sf_fractional = 0, /* Divide result by 4096 (Standard 4.12 fixed point) */ gte_sf_integer = 1, /* No division (Raw integer math) */ /* Matrix Select (Bits 18-17) - Which 3x3 matrix to multiply by */ gte_mx_rotation = 0, /* Rotation Matrix (RT) */ gte_mx_light = 1, /* Light Matrix (LL) */ gte_mx_color = 2, /* Color Matrix (LC) */ gte_mx_none = 3, /* Reserved / Do not multiply */ /* Vector select (Bits 16-15) - Which input vector to use */ gte_v_v0 = 0, /* Use Vector 0 (VXY0, VZ0) */ gte_v_v1 = 1, /* Use Vector 1 (VXY1, VZ1) */ gte_v_v2 = 2, /* Use Vector 2 (VXY2, VZ2) */ gte_v_ir_regs = 3, /* Use Intermediate Registers (IR1, IR2, IR3) */ /* Control Vector Select (Bits 14-13) - Which vector to ADD after multiplication */ gte_cv_translate = 0, /* Add Translation Vector (TRX, TRY, TRZ) */ gte_cv_bg_color = 1, /* Add Background Color (RBK, GBK, BBK) */ gte_cv_far_color = 2, /* Add Far Color (RFC, GFC, BFC) */ gte_cv_none = 3, /* Add Zero (No addition) */ /* Limit/Clamp (Bit 10) - Prevents overflow artifacts */ gte_lm_normal = 0, /* Normal math (can overflow) */ gte_lm_clamp = 1, /* Clamp results to valid hardware ranges (e.g., RGB 0-255) */ /* Core Command IDs (Bits 5-0) */ gte_cmd_rtps = 0x01, /* Rot/Trans Perspective Single (1 vertex) */ gte_cmd_rtpt = 0x02, /* Rot/Trans Perspective Triple (3 vertices) */ gte_cmd_nclip = 0x06, /* Normal Clipping (Backface culling) */ gte_cmd_op = 0x0C, /* Outer Product */ gte_cmd_mvmva = 0x12, /* Matrix Vector Multiply & Add (Custom math) */ /* --- GTE Command Bit-Field Layout --- * A GTE command word (sent to COP2 with RS=1) is laid out as: * * 31........25 24 23..19 18..17 16..15 14..13 12..11 10 9.......6 5.......0 * +------------+--+-----+------+------+------+------+---+--------+----------+ * | 0x3E (COP2)| 1| -- | sf | mx | v | cv | --| lm | -- | cmd | * +------------+--+-----+------+------+------+------+---+--------+----------+ * \_____ GTE_PAYLOAD _____/ \__ GTE_CMD __/ * * Shifts/masks below are the *bit positions* and *bit widths* of each * configurable field, used by the ENC_GTE_CMD encoder. Mirrors the * OPCODE_SHIFT / RS_SHIFT convention used in mips.h. */ gte_shift_sf = 19, gte_width_sf = 1, gte_mask_sf = 0x1, gte_shift_mx = 17, gte_width_mx = 2, gte_mask_mx = 0x3, gte_shift_v = 15, gte_width_v = 2, gte_mask_v = 0x3, gte_shift_cv = 13, gte_width_cv = 2, gte_mask_cv = 0x3, gte_shift_lm = 10, gte_width_lm = 1, gte_mask_lm = 0x1, gte_shift_cmd = 0, gte_width_cmd = 6, gte_mask_cmd = 0x3F, }; /* --- GTE Control Register Indices (for ctc2/cfc2) --- * Preprocessor-visible integer ids for the COP2 control register file. * Each enum value is bound to a parallel `_Code` `#define` so the * preprocessor can stringify the integer (for `reg_str`/`rgcc` paths). * Same pattern as the GPR `_Code` set in mips.h. Note: indices 21-23 * are reserved/unused on real hardware, so there's a gap. */ #define gte_cr_RT11_Code 0 #define gte_cr_RT12_Code 1 #define gte_cr_RT13_Code 2 #define gte_cr_RT21_Code 3 #define gte_cr_RT22_Code 4 #define gte_cr_RT23_Code 5 #define gte_cr_RT31_Code 6 #define gte_cr_RT32_Code 7 #define gte_cr_RT33_Code 8 #define gte_cr_TRX_Code 9 #define gte_cr_TRY_Code 10 #define gte_cr_TRZ_Code 11 #define gte_cr_L11_Code 12 #define gte_cr_L12_Code 13 #define gte_cr_L13_Code 14 #define gte_cr_L21_Code 15 #define gte_cr_L22_Code 16 #define gte_cr_L23_Code 17 #define gte_cr_LR1_Code 18 #define gte_cr_LR2_Code 19 #define gte_cr_LR3_Code 20 #define gte_cr_RBK_Code 24 #define gte_cr_GBK_Code 25 #define gte_cr_BBK_Code 26 #define gte_cr_RFC_Code 27 #define gte_cr_GFC_Code 28 #define gte_cr_BFC_Code 29 #define gte_cr_OFX_Code 30 #define gte_cr_OFY_Code 31 enum { gte_cr_RT11 = gte_cr_RT11_Code, gte_cr_RT12 = gte_cr_RT12_Code, gte_cr_RT13 = gte_cr_RT13_Code, gte_cr_RT21 = gte_cr_RT21_Code, gte_cr_RT22 = gte_cr_RT22_Code, gte_cr_RT23 = gte_cr_RT23_Code, gte_cr_RT31 = gte_cr_RT31_Code, gte_cr_RT32 = gte_cr_RT32_Code, gte_cr_RT33 = gte_cr_RT33_Code, gte_cr_TRX = gte_cr_TRX_Code, gte_cr_TRY = gte_cr_TRY_Code, gte_cr_TRZ = gte_cr_TRZ_Code, gte_cr_L11 = gte_cr_L11_Code, gte_cr_L12 = gte_cr_L12_Code, gte_cr_L13 = gte_cr_L13_Code, gte_cr_L21 = gte_cr_L21_Code, gte_cr_L22 = gte_cr_L22_Code, gte_cr_L23 = gte_cr_L23_Code, gte_cr_LR1 = gte_cr_LR1_Code, gte_cr_LR2 = gte_cr_LR2_Code, gte_cr_LR3 = gte_cr_LR3_Code, gte_cr_RBK = gte_cr_RBK_Code, gte_cr_GBK = gte_cr_GBK_Code, gte_cr_BBK = gte_cr_BBK_Code, gte_cr_RFC = gte_cr_RFC_Code, gte_cr_GFC = gte_cr_GFC_Code, gte_cr_BFC = gte_cr_BFC_Code, gte_cr_OFX = gte_cr_OFX_Code, gte_cr_OFY = gte_cr_OFY_Code, }; enum { _C2_OPS_ = 0 , op_lwc2 = 0x32 /* Load Word to Coprocessor 2 (GTE) */ , op_swc2 = 0x3A /* Store Word from Coprocessor 2 (GTE) */ }; /* COP2 (GTE) Transfer Format: ctc2 rt, rd or cfc2 rt, rd * Layout: [op_cop2:6][sub:5][rt:5][rd:5][0:11] * - sub: cop_mf (0x00) for cfc2, cop_mt (0x04) for ctc2 * - rt: GPR source/dest * - rd: COP2 control register index (0..31) */ #define enc_cop2_tx(sub, rt, rd) (enc_op(op_cop2) | enc_rs(sub) | enc_rt(rt) | enc_rd(rd)) /* COP2 Data Load (lwc2): `lwc2 rt, off(rs)` * Layout: [op_lwc2:6][rs:5][rt:5][imm:16] * - rs: GPR base address * - rt: COP2 data register index (0..31) * - imm: signed 16-bit offset * NOTE: When `rs` is a runtime register, the encoding cannot be pre-baked * into a .word — use the string-style `gte_load_v0` macro below instead. */ #define enc_cop2_lwc2(rt, base, off) enc_i(op_lwc2, (base), (rt), (off)) #define enc_cop2_swc2(rt, base, off) enc_i(op_swc2, (base), (rt), (off)) /* GTE Command Format (The math engine trigger) * Opcode is always MIPS_OP_COP2, RS is always 1 (CO). * The lower 25 bits are the GTE-specific command payload. * * The granular `enc_gte_(x)` macros below mirror the `enc_op`/`enc_rs` * pattern in mips.h: each one self-masks and shifts its own field, so a * caller can build up a GTE command piece by piece (handy for state-driven * MVMVA emitters that vary one field at a time). * * `ENC_GTE_CMD` is the all-in-one convenience for emitting a full command * word in one go. It just ORs the per-field encoders together. */ #define gte_cmd_base (enc_op(op_cop2) | (1 << 25)) /* Per-field encoders. Each one does (value & mask) << shift on its own. */ #define enc_gte_sf(sf) (((sf) & gte_mask_sf ) << gte_shift_sf ) #define enc_gte_mx(mx) (((mx) & gte_mask_mx ) << gte_shift_mx ) #define enc_gte_v(v) (((v) & gte_mask_v ) << gte_shift_v ) #define enc_gte_cv(cv) (((cv) & gte_mask_cv ) << gte_shift_cv ) #define enc_gte_lm(lm) (((lm) & gte_mask_lm ) << gte_shift_lm ) #define enc_gte_cmd(cmd) (((cmd) & gte_mask_cmd) << gte_shift_cmd) /* Composite: all six GTE fields + the COP2/CO base. */ #define enc_gte_cmdw(sf, mx, v, cv, lm, cmd) ( \ gte_cmd_base \ | enc_gte_sf(sf) \ | enc_gte_mx(mx) \ | enc_gte_v(v) \ | enc_gte_cv(cv) \ | enc_gte_lm(lm) \ | enc_gte_cmd(cmd) \ ) /** * @brief Loads a single SVECTOR to GTE vector register V0 * * @details Loads values from an SVECTOR struct to GTE data registers C2_VXY0 * (XY at offset 0) and C2_VZ0 (Z at offset 4) using `lwc2`. * * Uses string-style GCC inline asm with `%0` substitution because the * base register `r0` is a runtime GPR chosen by the compiler — it cannot * be encoded into a static `.word` constant. * * Usage: * asm_gte_load_v0(svector_ptr); */ /* Pre-baked lwc2 encoding helpers parameterized on the base GPR. * * gte_lwc2_v0(base) → lwc2 $0, 0(base) ; C2_VXY0 * gte_lwc2_v0z(base) → lwc2 $1, 4(base) ; C2_VZ0 * gte_lwc2_v1(base) → lwc2 $2, 0(base) ; C2_VXY1 * gte_lwc2_v1z(base) → lwc2 $3, 4(base) ; C2_VZ1 * gte_lwc2_v2(base) → lwc2 $4, 0(base) ; C2_VXY2 * gte_lwc2_v2z(base) → lwc2 $5, 4(base) ; C2_VZ2 * * `base` is the GPR number to bake into the .word constant's `rs` field. * These are pure compile-time integers; the C compiler constant-folds * them into .word directives. */ #define gte_lwc2_v0(base) enc_cop2_lwc2(gte_in_v0_xy, (base), 0) #define gte_lwc2_v0z(base) enc_cop2_lwc2(gte_in_v0_z, (base), 4) #define gte_lwc2_v1(base) enc_cop2_lwc2(gte_in_v1_xy, (base), 0) #define gte_lwc2_v1z(base) enc_cop2_lwc2(gte_in_v1_z, (base), 4) #define gte_lwc2_v2(base) enc_cop2_lwc2(gte_in_v2_xy, (base), 0) #define gte_lwc2_v2z(base) enc_cop2_lwc2(gte_in_v2_z, (base), 4) /* gte_load_vN(r_ptr, base) — placeholder-punned lwc2 loaders * * Emits `.word` constants encoding `lwc2 $N, off()` for the chosen * GTE vector register, where `` is the GPR number you pass in * (typically one of R_T4..R_T9 for the standard "3-pointer" pattern). * * The caller MUST bind `r_ptr` to that same GPR via a register variable: * * register V3_S2* p_in_12 __asm__("$12") = my_ptr; * gte_load_v0(p_in_12, R_T4); // R_T4 = 12, base is $12 * * Then `"r"(r_ptr)` inside the asm binds to $12 (the only register * `p_in_12` can live in), which is exactly the register the .word * constants expect. A `"$12"` clobber would conflict with the * register-variable binding ("asm specifier for variable conflicts * with asm clobber list"), so we omit it. The other ABI-clobbers * ($2/$8/$9/$31) stay because the GTE instructions don't touch * caller-saved GPRs but the kernel does treat them as volatile. * * WHICH REGISTER TO PICK * ---------------------- * Any caller-saved GPR is safe. Recommended default for an RTPT-style * 3-pointer pipeline: * gte_load_v0(p0, R_T4); // $12 * gte_load_v1(p1, R_T5); // $13 * gte_load_v2(p2, R_T6); // $14 * Avoid $0 (zero), $1 (at), $26/$27 (k0/k1), $28-$31 (gp/sp/fp/ra). * * Shape of the generated `asm volatile (...)`: * code section : ".word %0, %1" (from asm_inline) * outputs section : (empty, the 2nd colon) * inputs section : "i"(w0), "i"(w1), "r"(r_ptr) — r_ptr bound to * clobbers section : "$2", "$8", ..., "memory" (from asm_clobber) * 3 colons total, GCC-legal. No string-syntax mnemonics in the .word body. * * The `asm_clobber(...)` helper from gcc_asm.h prepends the colon that * starts the clobbers section. */ #define gte_load_v0(r_ptr, base) \ asm volatile( \ asm_inline( gte_lwc2_v0(base), gte_lwc2_v0z(base) ) \ , "r"(r_ptr) \ asm_clobber( reg_str(R_V0_Code), reg_str(R_T0_Code), reg_str(R_T1_Code), reg_str(R_RA_Code), "memory" ) \ ) #define gte_load_v1(r_ptr, base) \ asm volatile( \ asm_inline( gte_lwc2_v1(base), gte_lwc2_v1z(base) ) \ , "r"(r_ptr) \ asm_clobber( reg_str(R_V0_Code), reg_str(R_T0_Code), reg_str(R_T1_Code), reg_str(R_RA_Code), "memory" ) \ ) #define gte_load_v2(r_ptr, base) \ asm volatile( \ asm_inline( gte_lwc2_v2(base), gte_lwc2_v2z(base) ) \ , "r"(r_ptr) \ asm_clobber( reg_str(R_V0_Code), reg_str(R_T0_Code), reg_str(R_T1_Code), reg_str(R_RA_Code), "memory" ) \ ) /* gte_load_v0v1v2(p0, p1, p2, b0, b1, b2) — the canonical prelude to gte_cmd_rtpt. * * Loads all three GTE input vectors (6 words) from three separate pointers, * one per GTE vector register, each loaded from its own base GPR. Caller * must bind each `pN` to `bN` via a register variable. * * register V3_S2* p0 rgcc(R_T4) = verts[0].ptr; // → __asm__("$12") * register V3_S2* p1 rgcc(R_T5) = verts[1].ptr; // → __asm__("$13") * register V3_S2* p2 rgcc(R_T6) = verts[2].ptr; // → __asm__("$14") * gte_load_v0v1v2(p0, p1, p2, R_T4, R_T5, R_T6); * gte_rtpt(); */ #define gte_load_v0v1v2(p0, p1, p2, b0, b1, b2) \ asm volatile( \ asm_inline( gte_lwc2_v0(b0), gte_lwc2_v0z(b0), \ gte_lwc2_v1(b1), gte_lwc2_v1z(b1), \ gte_lwc2_v2(b2), gte_lwc2_v2z(b2) ) \ , "r"(p0), "r"(p1), "r"(p2) \ asm_clobber( reg_str(R_V0_Code), reg_str(R_T0_Code), reg_str(R_T1_Code), reg_str(R_RA_Code), "memory" ) \ ) #define gte_ldv0(r0) \ __asm__ volatile( \ "lwc2 $0, 0( %0 );" \ "lwc2 $1, 4( %0 )" \ : \ : "r"(r0)) #define gte_ldv1(r0) \ __asm__ volatile( \ "lwc2 $2, 0( %0 );" \ "lwc2 $3, 4( %0 )" \ : \ : "r"(r0)) #define gte_ldv2(r0) \ __asm__ volatile( \ "lwc2 $4, 0( %0 );" \ "lwc2 $5, 4( %0 )" \ : \ : "r"(r0)) #define gte_rtpt() \ __asm__ volatile( \ "nop;" \ "nop;" \ "cop2 0x0280030;") #define gte_nclip() \ __asm__ volatile( \ "nop;" \ "nop;" \ "cop2 0x01400006;") #define gte_stotz(r0) __asm__ volatile("swc2 $7, 0( %0 )" : : "r"(r0) : "memory") #define gte_stsxy3(r0, r1, r2) \ __asm__ volatile( \ "swc2 $12, 0( %0 );" \ "swc2 $13, 0( %1 );" \ "swc2 $14, 0( %2 )" \ : \ : "r"(r0), "r"(r1), "r"(r2) \ : "memory") #define gte_avsz3() \ __asm__ volatile( \ "nop;" \ "nop;" \ "cop2 0x0158002D;") /* asm_gte_matrix_set_rotation(r0) * * Loads the 3x3 rotation matrix at `r0` into the GTE's rotation-matrix * control registers (RT11..RT22, indices 0..4) via ctc2. * * Memory layout at r0: five contiguous 32-bit words (offsets 0..16), * each holding two packed 16-bit matrix elements. The first 1.5 rows * of a standard PSX SDK MATRIX struct (where each row is laid out as * [RT_xx, RT_xy] | [RT_xz, pad] | ...). * * Generated MIPS (mirrors the source macro): * * lw $12, 0( %0 ) ; word 0 * lw $13, 4( %0 ) ; word 1 * ctc2 $12, $0 ; → C2_RT11 * ctc2 $13, $1 ; → C2_RT12 * lw $12, 8( %0 ) ; word 2 * lw $13, 12( %0 ) ; word 3 * lw $14, 16( %0 ) ; word 4 * ctc2 $12, $2 ; → C2_RT13 * ctc2 $13, $3 ; → C2_RT21 * ctc2 $14, $4 ; → C2_RT22 * * Same contract as gte_load_v0: caller MUST bind `r0` to $12 via a * register variable (`rgcc(R_T4)`) for the `lw $12, off(...)` * instructions to read from the right base. The `"r"(r0)` constraint * alone doesn't force a specific GPR — it just lets GCC pick one. * The .word constants here bake R_T4/R_T5/R_T6 into the `rs` field * of each lw, so the lw instructions will only do the right thing * if $12/$13/$14 hold the matrix base at runtime. * * M3_S2* m = ...; * register M3_S2* m_in_12 rgcc(R_T4) = m; * asm_gte_matrix_set_rotation(m_in_12); * * We clobber $12/$13/$14 (the ones we use as scratch inside the * inline asm) plus the system clobbers; we don't clobber `r0` because * the `rgcc` binding already says "this variable lives in $12". * * WARNING: Incomplete by design. The source macro only writes RT11..RT22 * (5 of 9 rotation elements); RT23 and the entire RT3x row are left * untouched. Real libpsn00b SetRotMatrix writes all 9. Use only when the * GTE's remaining rotation entries are already correct, or you will * get stale-RT2x/RT3x artifacts in RTPS/RTPT/MVMVA output. */ #define asm_gte_matrix_set_rotation(r0) \ asm volatile( \ asm_inline( \ load_imm(R_T4, r0, 0), \ load_imm(R_T5, r0, 4), \ enc_cop2_tx(cop_mt, R_T4, 0), \ enc_cop2_tx(cop_mt, R_T5, 1), \ load_imm(R_T4, r0, 8), \ load_imm(R_T5, r0, 12), \ load_imm(R_T6, r0, 16), \ enc_cop2_tx(cop_mt, R_T4, 2), \ enc_cop2_tx(cop_mt, R_T5, 3), \ enc_cop2_tx(cop_mt, R_T6, 4) \ ) \ asm_clobber( clb_system, reg_str(R_T4_Code), reg_str(R_T5_Code), reg_str(R_T6_Code) ) \ : \ : "r"(r0) \ )