| %default { "naninst":"mvn r0, #0" } |
| /* |
| * For the JIT: incoming arguments in r0-r1, r2-r3 |
| * result in r0 |
| * |
| * Compare two floating-point values. Puts 0, 1, or -1 into the |
| * destination register based on the results of the comparison. |
| * |
| * Provide a "naninst" instruction that puts 1 or -1 into r1 depending |
| * on what value we'd like to return when one of the operands is NaN. |
| * |
| * The operation we're implementing is: |
| * if (x == y) |
| * return 0; |
| * else if (x < y) |
| * return -1; |
| * else if (x > y) |
| * return 1; |
| * else |
| * return {-1,1}; // one or both operands was NaN |
| * |
| * The straightforward implementation requires 3 calls to functions |
| * that return a result in r0. We can do it with two calls if our |
| * EABI library supports __aeabi_cfcmple (only one if we want to check |
| * for NaN directly): |
| * check x <= y |
| * if <, return -1 |
| * if ==, return 0 |
| * check y <= x |
| * if <, return 1 |
| * return {-1,1} |
| * |
| * for: cmpl-float, cmpg-float |
| */ |
| /* op vAA, vBB, vCC */ |
| mov r9, r0 @ Save copies - we may need to redo |
| mov r10, r1 |
| mov r11, lr @ save return address |
| LDR_PC_LR ".L__aeabi_cfcmple" @ cmp <=: C clear if <, Z set if eq |
| bhi .L${opcode}_gt_or_nan @ C set and Z clear, disambiguate |
| mvncc r0, #0 @ (less than) r0<- -1 |
| moveq r0, #0 @ (equal) r0<- 0, trumps less than |
| bx r11 |
| @ Test for NaN with a second comparison. EABI forbids testing bit |
| @ patterns, and we can't represent 0x7fc00000 in immediate form, so |
| @ make the library call. |
| .L${opcode}_gt_or_nan: |
| mov r0, r10 @ restore in reverse order |
| mov r1, r9 |
| LDR_PC_LR ".L__aeabi_cfcmple" @ r0<- Z set if eq, C clear if < |
| movcc r0, #1 @ (greater than) r1<- 1 |
| bxcc r11 |
| $naninst @ r1<- 1 or -1 for NaN |
| bx r11 |
