From 023020d740b4fb5da2b9f344d97d1c151e7bbb90 Mon Sep 17 00:00:00 2001 From: Brian Paul Date: Sat, 18 Jan 2014 04:28:47 -0800 Subject: [PATCH] svga: add comments, etc to svga_tgsi_insn.c code MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit To make things a little easier to understand for newcomers. Reviewed-by: José Fonseca --- src/gallium/drivers/svga/svga_tgsi_insn.c | 194 ++++++++++++++++++---- 1 file changed, 163 insertions(+), 31 deletions(-) diff --git a/src/gallium/drivers/svga/svga_tgsi_insn.c b/src/gallium/drivers/svga/svga_tgsi_insn.c index ce00da6fc0b..062579be5d6 100644 --- a/src/gallium/drivers/svga/svga_tgsi_insn.c +++ b/src/gallium/drivers/svga/svga_tgsi_insn.c @@ -56,8 +56,7 @@ translate_opcode(uint opcode) case TGSI_OPCODE_NOP: return SVGA3DOP_NOP; case TGSI_OPCODE_NRM4: return SVGA3DOP_NRM; default: - debug_printf("Unkown opcode %u\n", opcode); - assert( 0 ); + assert(!"svga: unexpected opcode in translate_opcode()"); return SVGA3DOP_LAST_INST; } } @@ -75,12 +74,17 @@ translate_file(unsigned file) case TGSI_FILE_SAMPLER: return SVGA3DREG_SAMPLER; case TGSI_FILE_ADDRESS: return SVGA3DREG_ADDR; default: - assert( 0 ); + assert(!"svga: unexpected register file in translate_file()"); return SVGA3DREG_TEMP; } } +/** + * Translate a TGSI destination register to an SVGA3DShaderDestToken. + * \param insn the TGSI instruction + * \param idx which TGSI dest register to translate (usually (always?) zero) + */ static SVGA3dShaderDestToken translate_dst_register( struct svga_shader_emitter *emit, const struct tgsi_full_instruction *insn, @@ -184,6 +188,9 @@ svga_arl_adjustment( const struct svga_shader_emitter *emit ) } +/** + * Translate a TGSI src register to a src_register. + */ static struct src_register translate_src_register( const struct svga_shader_emitter *emit, const struct tgsi_full_src_register *reg ) @@ -300,6 +307,9 @@ release_temp( struct svga_shader_emitter *emit, } +/** + * Release all temps. + */ static void reset_temp_regs(struct svga_shader_emitter *emit) { @@ -472,6 +482,9 @@ emit_repl(struct svga_shader_emitter *emit, } +/** + * Submit/emit an instruction with zero operands. + */ static boolean submit_op0(struct svga_shader_emitter *emit, SVGA3dShaderInstToken inst, @@ -482,6 +495,9 @@ submit_op0(struct svga_shader_emitter *emit, } +/** + * Submit/emit an instruction with one operand. + */ static boolean submit_op1(struct svga_shader_emitter *emit, SVGA3dShaderInstToken inst, @@ -493,6 +509,8 @@ submit_op1(struct svga_shader_emitter *emit, /** + * Submit/emit an instruction with two operands. + * * SVGA shaders may not refer to >1 constant register in a single * instruction. This function checks for that usage and inserts a * move to temporary if detected. @@ -543,6 +561,8 @@ submit_op2(struct svga_shader_emitter *emit, /** + * Submit/emit an instruction with three operands. + * * SVGA shaders may not refer to >1 constant register in a single * instruction. This function checks for that usage and inserts a * move to temporary if detected. @@ -613,6 +633,8 @@ submit_op3(struct svga_shader_emitter *emit, /** + * Submit/emit an instruction with four operands. + * * SVGA shaders may not refer to >1 constant register in a single * instruction. This function checks for that usage and inserts a * move to temporary if detected. @@ -706,6 +728,9 @@ alias_src_dst(struct src_register src, } +/** + * Translate/emit a LRP (linear interpolation) instruction. + */ static boolean submit_lrp(struct svga_shader_emitter *emit, SVGA3dShaderDestToken dst, @@ -742,6 +767,10 @@ submit_lrp(struct svga_shader_emitter *emit, } +/** + * Helper for emitting SVGA immediate values using the SVGA3DOP_DEF[I] + * instructions. + */ static boolean emit_def_const(struct svga_shader_emitter *emit, SVGA3dShaderConstType type, @@ -781,6 +810,11 @@ emit_def_const(struct svga_shader_emitter *emit, } +/** + * Create/emit a constant with values {0, 0.5, -1, 1}. + * We can swizzle this to produce other useful constants such as + * {0, 0, 0, 0}, {1, 1, 1, 1}, etc. + */ static boolean create_zero_immediate( struct svga_shader_emitter *emit ) { @@ -943,8 +977,8 @@ get_fake_arl_const( struct svga_shader_emitter *emit ) /** - * Return the register which holds the current dimenions of the - * texture bound to the given sampler + * Return a register which holds the width and height of the texture + * currently bound to the given sampler. */ static struct src_register get_tex_dimensions( struct svga_shader_emitter *emit, int sampler_num ) @@ -1241,6 +1275,9 @@ emit_nrm(struct svga_shader_emitter *emit, } +/** + * Sine / Cosine helper function. + */ static boolean do_emit_sincos(struct svga_shader_emitter *emit, SVGA3dShaderDestToken dst, @@ -1251,6 +1288,9 @@ do_emit_sincos(struct svga_shader_emitter *emit, } +/** + * Translate/emit a TGSI SIN, COS or CSC instruction. + */ static boolean emit_sincos(struct svga_shader_emitter *emit, const struct tgsi_full_instruction *insn) @@ -1272,6 +1312,7 @@ emit_sincos(struct svga_shader_emitter *emit, /** + * Translate TGSI SIN instruction into: * SCS TMP SRC * MOV DST TMP.yyyy */ @@ -1297,7 +1338,9 @@ emit_sin(struct svga_shader_emitter *emit, return TRUE; } + /* + * Translate TGSI COS instruction into: * SCS TMP SRC * MOV DST TMP.xxxx */ @@ -1324,6 +1367,9 @@ emit_cos(struct svga_shader_emitter *emit, } +/** + * Translate/emit TGSI SSG (Set Sign: -1, 0, +1) instruction. + */ static boolean emit_ssg(struct svga_shader_emitter *emit, const struct tgsi_full_instruction *insn) @@ -1363,7 +1409,8 @@ emit_ssg(struct svga_shader_emitter *emit, /** - * ADD DST SRC0, negate(SRC0) + * Translate/emit TGSI SUB instruction as: + * ADD DST, SRC0, negate(SRC1) */ static boolean emit_sub(struct svga_shader_emitter *emit, @@ -1385,6 +1432,9 @@ emit_sub(struct svga_shader_emitter *emit, } +/** + * Translate/emit KILL_IF instruction (kill if any of X,Y,Z,W are negative). + */ static boolean emit_kill_if(struct svga_shader_emitter *emit, const struct tgsi_full_instruction *insn) @@ -1426,7 +1476,8 @@ emit_kill_if(struct svga_shader_emitter *emit, /** - * unconditional kill + * Translate/emit unconditional kill instruction (usually found inside + * an IF/ELSE/ENDIF block). */ static boolean emit_kill(struct svga_shader_emitter *emit, @@ -1461,7 +1512,8 @@ same_register(struct src_register r1, struct src_register r2) -/* Implement conditionals by initializing destination reg to 'fail', +/** + * Implement conditionals by initializing destination reg to 'fail', * then set predicate reg with UFOP_SETP, then move 'pass' to dest * based on predicate reg. * @@ -1547,6 +1599,13 @@ emit_conditional(struct svga_shader_emitter *emit, } +/** + * Helper for emiting 'selection' commands. Basically: + * if (src0 OP src1) + * dst = 1.0; + * else + * dst = 0.0; + */ static boolean emit_select(struct svga_shader_emitter *emit, unsigned compare_func, @@ -1581,17 +1640,14 @@ emit_select(struct svga_shader_emitter *emit, one = scalar( zero, TGSI_SWIZZLE_W ); zero = scalar( zero, TGSI_SWIZZLE_X ); - return emit_conditional( - emit, - compare_func, - dst, - src0, - src1, - one, zero); + return emit_conditional(emit, compare_func, dst, src0, src1, one, zero); } } +/** + * Translate/emit a TGSI SEQ, SNE, SLT, SGE, etc. instruction. + */ static boolean emit_select_op(struct svga_shader_emitter *emit, unsigned compare, @@ -1608,7 +1664,8 @@ emit_select_op(struct svga_shader_emitter *emit, /** - * Translate TGSI CMP instruction. + * Translate TGSI CMP instruction. Component-wise: + * dst = (src0 < 0.0) ? src1 : src2 */ static boolean emit_cmp(struct svga_shader_emitter *emit, @@ -1644,7 +1701,7 @@ emit_cmp(struct svga_shader_emitter *emit, /** - * Translate texture instructions to SVGA3D representation. + * Translate/emit 2-operand (coord, sampler) texture instructions. */ static boolean emit_tex2(struct svga_shader_emitter *emit, @@ -1729,7 +1786,7 @@ emit_tex2(struct svga_shader_emitter *emit, /** - * Translate texture instructions to SVGA3D representation. + * Translate/emit 4-operand (coord, ddx, ddy, sampler) texture instructions. */ static boolean emit_tex4(struct svga_shader_emitter *emit, @@ -1763,7 +1820,8 @@ emit_tex4(struct svga_shader_emitter *emit, /** - * Emit texture swizzle code. + * Emit texture swizzle code. We do this here since SVGA samplers don't + * directly support swizzles. */ static boolean emit_tex_swizzle(struct svga_shader_emitter *emit, @@ -1830,6 +1888,9 @@ emit_tex_swizzle(struct svga_shader_emitter *emit, } +/** + * Translate/emit a TGSI texture sample instruction. + */ static boolean emit_tex(struct svga_shader_emitter *emit, const struct tgsi_full_instruction *insn) @@ -1957,8 +2018,8 @@ emit_tex(struct svga_shader_emitter *emit, static boolean -emit_bgnloop2(struct svga_shader_emitter *emit, - const struct tgsi_full_instruction *insn) +emit_bgnloop(struct svga_shader_emitter *emit, + const struct tgsi_full_instruction *insn) { SVGA3dShaderInstToken inst = inst_token( SVGA3DOP_LOOP ); struct src_register loop_reg = src_register( SVGA3DREG_LOOP, 0 ); @@ -1973,8 +2034,8 @@ emit_bgnloop2(struct svga_shader_emitter *emit, static boolean -emit_endloop2(struct svga_shader_emitter *emit, - const struct tgsi_full_instruction *insn) +emit_endloop(struct svga_shader_emitter *emit, + const struct tgsi_full_instruction *insn) { SVGA3dShaderInstToken inst = inst_token( SVGA3DOP_ENDLOOP ); @@ -1984,6 +2045,9 @@ emit_endloop2(struct svga_shader_emitter *emit, } +/** + * Translate/emit TGSI BREAK (out of loop) instruction. + */ static boolean emit_brk(struct svga_shader_emitter *emit, const struct tgsi_full_instruction *insn) @@ -1993,6 +2057,10 @@ emit_brk(struct svga_shader_emitter *emit, } +/** + * Emit simple instruction which operates on one scalar value (not + * a vector). Ex: LG2, RCP, RSQ. + */ static boolean emit_scalar_op1(struct svga_shader_emitter *emit, unsigned opcode, @@ -2011,6 +2079,10 @@ emit_scalar_op1(struct svga_shader_emitter *emit, } +/** + * Translate/emit a simple instruction (one which has no special-case + * code) such as ADD, MUL, MIN, MAX. + */ static boolean emit_simple_instruction(struct svga_shader_emitter *emit, unsigned opcode, @@ -2045,6 +2117,9 @@ emit_simple_instruction(struct svga_shader_emitter *emit, } +/** + * Translate/emit TGSI DDX, DDY instructions. + */ static boolean emit_deriv(struct svga_shader_emitter *emit, const struct tgsi_full_instruction *insn ) @@ -2104,6 +2179,11 @@ emit_deriv(struct svga_shader_emitter *emit, } +/** + * Translate/emit ARL (Address Register Load) instruction. Used to + * move a value into the special 'address' register. Used to implement + * indirect/variable indexing into arrays. + */ static boolean emit_arl(struct svga_shader_emitter *emit, const struct tgsi_full_instruction *insn) @@ -2165,6 +2245,9 @@ emit_pow(struct svga_shader_emitter *emit, } +/** + * Translate/emit TGSI XPD (vector cross product) instruction. + */ static boolean emit_xpd(struct svga_shader_emitter *emit, const struct tgsi_full_instruction *insn) @@ -2219,6 +2302,9 @@ emit_xpd(struct svga_shader_emitter *emit, } +/** + * Translate/emit LRP (Linear Interpolation) instruction. + */ static boolean emit_lrp(struct svga_shader_emitter *emit, const struct tgsi_full_instruction *insn) @@ -2234,7 +2320,9 @@ emit_lrp(struct svga_shader_emitter *emit, return submit_lrp(emit, dst, src0, src1, src2); } - +/** + * Translate/emit DST (Distance function) instruction. + */ static boolean emit_dst_insn(struct svga_shader_emitter *emit, const struct tgsi_full_instruction *insn) @@ -2379,6 +2467,9 @@ emit_exp(struct svga_shader_emitter *emit, } +/** + * Translate/emit LIT (Lighting helper) instruction. + */ static boolean emit_lit(struct svga_shader_emitter *emit, const struct tgsi_full_instruction *insn) @@ -2692,6 +2783,9 @@ emit_trunc_round(struct svga_shader_emitter *emit, } +/** + * Translate/emit "begin subroutine" instruction/marker/label. + */ static boolean emit_bgnsub(struct svga_shader_emitter *emit, unsigned position, @@ -2718,6 +2812,9 @@ emit_bgnsub(struct svga_shader_emitter *emit, } +/** + * Translate/emit subroutine call instruction. + */ static boolean emit_call(struct svga_shader_emitter *emit, const struct tgsi_full_instruction *insn) @@ -2759,7 +2856,9 @@ emit_end(struct svga_shader_emitter *emit) } - +/** + * Translate any TGSI instruction to SVGA. + */ static boolean svga_emit_instruction(struct svga_shader_emitter *emit, unsigned position, @@ -2910,9 +3009,9 @@ svga_emit_instruction(struct svga_shader_emitter *emit, return emit_endif( emit, insn ); case TGSI_OPCODE_BGNLOOP: - return emit_bgnloop2( emit, insn ); + return emit_bgnloop( emit, insn ); case TGSI_OPCODE_ENDLOOP: - return emit_endloop2( emit, insn ); + return emit_endloop( emit, insn ); case TGSI_OPCODE_BRK: return emit_brk( emit, insn ); @@ -2950,9 +3049,13 @@ svga_emit_instruction(struct svga_shader_emitter *emit, } +/** + * Translate/emit a TGSI IMMEDIATE declaration. + * An immediate vector is a constant that's hard-coded into the shader. + */ static boolean svga_emit_immediate(struct svga_shader_emitter *emit, - struct tgsi_full_immediate *imm) + const struct tgsi_full_immediate *imm) { static const float id[4] = {0,0,0,1}; float value[4]; @@ -2964,6 +3067,9 @@ svga_emit_immediate(struct svga_shader_emitter *emit, value[i] = util_is_inf_or_nan(f) ? 0.0f : f; } + /* If the immediate has less than four values, fill in the remaining + * positions from id={0,0,0,1}. + */ for ( ; i < 4; i++ ) value[i] = id[i]; @@ -2990,6 +3096,9 @@ make_immediate(struct svga_shader_emitter *emit, } +/** + * Emit special VS instructions at top of shader. + */ static boolean emit_vs_preamble(struct svga_shader_emitter *emit) { @@ -3003,6 +3112,9 @@ emit_vs_preamble(struct svga_shader_emitter *emit) } +/** + * Emit special PS instructions at top of shader. + */ static boolean emit_ps_preamble(struct svga_shader_emitter *emit) { @@ -3040,6 +3152,9 @@ emit_ps_preamble(struct svga_shader_emitter *emit) } +/** + * Emit special PS instructions at end of shader. + */ static boolean emit_ps_postamble(struct svga_shader_emitter *emit) { @@ -3097,6 +3212,9 @@ emit_ps_postamble(struct svga_shader_emitter *emit) } +/** + * Emit special VS instructions at end of shader. + */ static boolean emit_vs_postamble(struct svga_shader_emitter *emit) { @@ -3199,6 +3317,7 @@ emit_vs_postamble(struct svga_shader_emitter *emit) /** * For the pixel shader: emit the code which chooses the front * or back face color depending on triangle orientation. + * This happens at the top of the fragment shader. * * 0: IF VFACE :4 * 1: COLOR = FrontColor; @@ -3276,6 +3395,7 @@ emit_light_twoside(struct svga_shader_emitter *emit) /** + * Emit special setup code for the front/back face register in the FS. * 0: SETP_GT TEMP, VFACE, 0 * where TEMP is a fake frontface register */ @@ -3361,8 +3481,13 @@ emit_inverted_texcoords(struct svga_shader_emitter *emit) } +/** + * Determine if we need to emit an immediate value with zeros. + * We could just do this all the time except that we want to conserve + * registers whenever possible. + */ static boolean -needs_to_create_zero( struct svga_shader_emitter *emit ) +needs_to_create_zero(const struct svga_shader_emitter *emit) { unsigned i; @@ -3426,15 +3551,18 @@ needs_to_create_zero( struct svga_shader_emitter *emit ) } +/** + * Do we need to create a looping constant? + */ static boolean -needs_to_create_loop_const( struct svga_shader_emitter *emit ) +needs_to_create_loop_const(const struct svga_shader_emitter *emit) { return (emit->info.opcode_count[TGSI_OPCODE_BGNLOOP] >= 1); } static boolean -needs_to_create_arl_consts( struct svga_shader_emitter *emit ) +needs_to_create_arl_consts(const struct svga_shader_emitter *emit) { return (emit->num_arl_consts > 0); } @@ -3564,6 +3692,10 @@ svga_shader_emit_helpers(struct svga_shader_emitter *emit) } +/** + * This is the main entrypoint into the TGSI instruction translater. + * Translate TGSI shader tokens into an SVGA shader. + */ boolean svga_shader_emit_instructions(struct svga_shader_emitter *emit, const struct tgsi_token *tokens) -- 2.30.2