v5: simplify: move JBSMATCH_OPCODE block outside nested switch

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   3884	      0	      0	   3884	    f2c	apf_interpreter.arm.o
   text	   data	    bss	    dec	    hex	filename
   4822	      0	      0	   4822	   12d6	apf_interpreter.x86.o
After:
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   3912	      0	      0	   3912	    f48	apf_interpreter.arm.o
   text	   data	    bss	    dec	    hex	filename
   4829	      0	      0	   4829	   12dd	apf_interpreter.x86.o

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Ib1901d09182297e6feeadb83f01dbe0be17b636d

2 files changed, 54 insertions, 40 deletions

diff --git a/v5/apf_interpreter.c b/v5/apf_interpreter.c
index 1b03c50..f3b6726 100644
--- a/v5/apf_interpreter.c
+++ b/v5/apf_interpreter.c
@@ -769,8 +769,7 @@ static int do_apf_run(apf_context* ctx) {
           case JNE_OPCODE:
           case JGT_OPCODE:
           case JLT_OPCODE:
-          case JSET_OPCODE:
-          case JBSMATCH_OPCODE: {
+          case JSET_OPCODE: {
               /* Load second immediate field. */
               u32 cmp_imm = 0;
               if (reg_num == 1) {
@@ -785,27 +784,35 @@ static int do_apf_run(apf_context* ctx) {
                   case JGT_OPCODE:  if (ctx->R[0] >  cmp_imm) ctx->pc += imm; break;
                   case JLT_OPCODE:  if (ctx->R[0] <  cmp_imm) ctx->pc += imm; break;
                   case JSET_OPCODE: if (ctx->R[0] &  cmp_imm) ctx->pc += imm; break;
-                  case JBSMATCH_OPCODE: {
-                      /* cmp_imm is size in bytes of data to compare. */
-                      /* pc is offset of program bytes to compare. */
-                      /* imm is jump target offset. */
-                      /* REG is offset of packet bytes to compare. */
-                      if (len_field > 2) return PASS_PACKET; /* guarantees cmp_imm <= 0xFFFF */
-                      /* pc < program_len < ram_len < 2GiB, thus pc + cmp_imm cannot wrap */
-                      if (!IN_RAM_BOUNDS(ctx->pc + cmp_imm - 1)) return PASS_PACKET;
-                      ASSERT_IN_PACKET_BOUNDS(REG);
-                      const u32 last_packet_offs = REG + cmp_imm - 1;
-                      ASSERT_RETURN(last_packet_offs >= REG);
-                      ASSERT_IN_PACKET_BOUNDS(last_packet_offs);
-                      if (memcmp(ctx->program + ctx->pc, ctx->packet + REG, cmp_imm))
-                          ctx->pc += imm;
-                      /* skip past comparison bytes */
-                      ctx->pc += cmp_imm;
-                      break;
-                  }
               }
               break;
           }
+          case JBSMATCH_OPCODE: {
+              /* Load second immediate field. */
+              u32 cmp_imm = 0;
+              if (reg_num == 1) {
+                  cmp_imm = ctx->R[1];
+              } else if (len_field != 0) {
+                  u32 cmp_imm_len = 1 << (len_field - 1);
+                  cmp_imm = decode_imm(ctx, cmp_imm_len); /* 2nd imm, at worst 8 bytes past prog_len */
+              }
+              /* cmp_imm is size in bytes of data to compare. */
+              /* pc is offset of program bytes to compare. */
+              /* imm is jump target offset. */
+              /* REG is offset of packet bytes to compare. */
+              if (len_field > 2) return PASS_PACKET; /* guarantees cmp_imm <= 0xFFFF */
+              /* pc < program_len < ram_len < 2GiB, thus pc + cmp_imm cannot wrap */
+              if (!IN_RAM_BOUNDS(ctx->pc + cmp_imm - 1)) return PASS_PACKET;
+              ASSERT_IN_PACKET_BOUNDS(REG);
+              const u32 last_packet_offs = REG + cmp_imm - 1;
+              ASSERT_RETURN(last_packet_offs >= REG);
+              ASSERT_IN_PACKET_BOUNDS(last_packet_offs);
+              if (memcmp(ctx->program + ctx->pc, ctx->packet + REG, cmp_imm))
+                  ctx->pc += imm;
+              /* skip past comparison bytes */
+              ctx->pc += cmp_imm;
+              break;
+          }
           /* There is a difference in APFv4 and APFv6 arithmetic behaviour! */
           /* APFv4:  R[0] op= Rbit ? R[1] : imm;  (and it thus doesn't make sense to have R=1 && len_field>0) */
           /* APFv6+: REG  op= len_field ? imm : OTHER_REG;  (note: this is *DIFFERENT* with R=1 len_field==0) */
diff --git a/v5/apf_interpreter_source.c b/v5/apf_interpreter_source.c
index c0552e7..5b8b4cc 100644
--- a/v5/apf_interpreter_source.c
+++ b/v5/apf_interpreter_source.c
@@ -236,8 +236,7 @@ static int do_apf_run(apf_context* ctx) {
           case JNE_OPCODE:
           case JGT_OPCODE:
           case JLT_OPCODE:
-          case JSET_OPCODE:
-          case JBSMATCH_OPCODE: {
+          case JSET_OPCODE: {
               // Load second immediate field.
               u32 cmp_imm = 0;
               if (reg_num == 1) {
@@ -252,27 +251,35 @@ static int do_apf_run(apf_context* ctx) {
                   case JGT_OPCODE:  if (ctx->R[0] >  cmp_imm) ctx->pc += imm; break;
                   case JLT_OPCODE:  if (ctx->R[0] <  cmp_imm) ctx->pc += imm; break;
                   case JSET_OPCODE: if (ctx->R[0] &  cmp_imm) ctx->pc += imm; break;
-                  case JBSMATCH_OPCODE: {
-                      // cmp_imm is size in bytes of data to compare.
-                      // pc is offset of program bytes to compare.
-                      // imm is jump target offset.
-                      // REG is offset of packet bytes to compare.
-                      if (len_field > 2) return PASS_PACKET; // guarantees cmp_imm <= 0xFFFF
-                      // pc < program_len < ram_len < 2GiB, thus pc + cmp_imm cannot wrap
-                      if (!IN_RAM_BOUNDS(ctx->pc + cmp_imm - 1)) return PASS_PACKET;
-                      ASSERT_IN_PACKET_BOUNDS(REG);
-                      const u32 last_packet_offs = REG + cmp_imm - 1;
-                      ASSERT_RETURN(last_packet_offs >= REG);
-                      ASSERT_IN_PACKET_BOUNDS(last_packet_offs);
-                      if (memcmp(ctx->program + ctx->pc, ctx->packet + REG, cmp_imm))
-                          ctx->pc += imm;
-                      // skip past comparison bytes
-                      ctx->pc += cmp_imm;
-                      break;
-                  }
               }
               break;
           }
+          case JBSMATCH_OPCODE: {
+              // Load second immediate field.
+              u32 cmp_imm = 0;
+              if (reg_num == 1) {
+                  cmp_imm = ctx->R[1];
+              } else if (len_field != 0) {
+                  u32 cmp_imm_len = 1 << (len_field - 1);
+                  cmp_imm = decode_imm(ctx, cmp_imm_len); // 2nd imm, at worst 8 bytes past prog_len
+              }
+              // cmp_imm is size in bytes of data to compare.
+              // pc is offset of program bytes to compare.
+              // imm is jump target offset.
+              // REG is offset of packet bytes to compare.
+              if (len_field > 2) return PASS_PACKET; // guarantees cmp_imm <= 0xFFFF
+              // pc < program_len < ram_len < 2GiB, thus pc + cmp_imm cannot wrap
+              if (!IN_RAM_BOUNDS(ctx->pc + cmp_imm - 1)) return PASS_PACKET;
+              ASSERT_IN_PACKET_BOUNDS(REG);
+              const u32 last_packet_offs = REG + cmp_imm - 1;
+              ASSERT_RETURN(last_packet_offs >= REG);
+              ASSERT_IN_PACKET_BOUNDS(last_packet_offs);
+              if (memcmp(ctx->program + ctx->pc, ctx->packet + REG, cmp_imm))
+                  ctx->pc += imm;
+              // skip past comparison bytes
+              ctx->pc += cmp_imm;
+              break;
+          }
           // There is a difference in APFv4 and APFv6 arithmetic behaviour!
           // APFv4:  R[0] op= Rbit ? R[1] : imm;  (and it thus doesn't make sense to have R=1 && len_field>0)
           // APFv6+: REG  op= len_field ? imm : OTHER_REG;  (note: this is *DIFFERENT* with R=1 len_field==0)